Reduction of the cultivation of maize landraces in the families and municipalities
Based on the 56 interviews we were able to complete (10 of the original 66 families were not found), it was evident that the importance of maize cultivation in general had diminished over the last 50 years among the families who donated seed to the Bank in 1967. Among the interviewed families, 50% were still cultivating maize among their crops, 11% were exclusively cultivating other crops and 24% of them were no longer involved in agriculture (Table 1).
The importance of landrace cultivation, in particular, had diminished even further among the families. In 2017, 67% of the families who were still cultivating maize (33% of the total) were growing landraces. This reduction coincided with the introduction of improved maize varieties, which farmers refer to as hybrids. Hybrids, which were not present among the families in 1967, were since adopted by 42% of the families still cultivating maize in 2017 (21% of the total). The coexistence of hybrids and landraces in a family farm was uncommon, reported only in 4% percent of the interviewed families.
The 22 families who were still cultivating landraces in 2017 fell into three categories: (1) those who had conserved the same seed lot they donated to the Bank in 1967 under constant cultivation during the 50-year period (13 families); (2) those who had conserved the same landrace they donated to the Bank in 1967 but from a different seed lot obtained from a family member, a neighbor or from the market (five families); and (3) those who had lost the seed lot from 1967 and later introduced a seed lot of a different landrace (four families). Families in the first category conserved 14 of the 93 accessions collected in 1967, while families in the second category conserved six accessions. Together, these families had conserved 15% of the collection’s accessions of the same seed lot and 22% of the same landrace (Table 2; Fig. 3). These data indicate that the families were still conserving only a small portion of the diversity present in the 1967 collection. Additionally, families in the three categories had introduced 13 landrace seed lots that were not present in 1967.
Focus group discussions included a total of 103 participants. Between three and ten farmers attended each meeting. Participants’ ages ranged between 33 and 86 years old, averaging 65 years old. Farmers had between 4 and 72 years of farming experience (44 years on average) and between 2 and 72 years of maize landrace cultivation experience (41 years on average).
Data gathered from the focus groups suggested that the changes in presence/absence and diversity of landraces in the municipalities (meta-population level) were less pronounced than those in the families, but followed similar trends. Based on the photographs of the 1967 collections, participants identified 60 accessions that could still be found in the corresponding municipalities. Thus, the municipalities had conserved 65% of the collection’s accessions of the same landrace (Table 2). Seventeen accessions overlapped with those conserved by families from the first two categories described above, but 43 accessions had only been conserved at the municipality level. The remaining 30 accessions had been abandoned, both by the families and in the municipalities.
Regardless of the presence/absence of the targeted accessions, farmers reported that the predominant trend for all landraces in their municipalities was towards a reduction in their cultivation (Table 3). Although they were present, most landraces were being cultivated by fewer farmers and in smaller areas in the municipalities. Moreover, most landraces were present in fewer municipalities, and some landraces, such as Cuarenteño and Itzihuine, had disappeared from the study area. Only the cultivation of Ancho, Negro, Arrocillo and Criollo increased in one or more municipalities. Meanwhile hybrids, which farmers did not recall being present around 1967, had become widespread.
We determined that the occurrences of the different landraces in the 1967 collection matched the occurrences that the farmers recalled in the municipalities at the time (Table 3). Among the most common landraces, Ancho was widespread in 13 municipalities and Pepitilla in ten, planted by many farmers in large areas. The colored landraces (Negro, black maize; Azul, blue maize; Rojo or Colorado, red maize) were present in several municipalities and were planted by many farmers, but in small areas. Criollo and Del Monte were present in just a few municipalities, but planted by many farmers in large areas.
The relative occurrence of different landraces changed over time, as it was not the same in the 1967 collection as in the seed lots from the collection conserved in the families and municipalities (Table 2). Ancho remained the most common landrace, but the occurrence of Delgado decreased in situ. Other landraces such as Negro and Colorado, less abundant in 1967, were better represented in 2017. A similar trend was observed for these landraces in the discussion with focus group participants (Table 3).
A multilevel perspective on why farmers reduced the cultivation of maize landraces
Radical innovation: the introduction of maize hybrids
Maize breeders and farmers in the USA introduced hybrids in the 1930s as an alternative technology to landraces, starting what eventually became the Green Revolution (Duvick 1996; Pistorius 1997). Their Mexican counterparts soon followed. At the time, the advantages of this new technology were based on two principles: the selection and fixation of qualitative traits and the manipulation of hybrid vigor. Breeding for qualitative traits relied on well-understood Mendelian inheritance principles. Pest and disease resistance were the best candidates among these traits, ranking high among farmers’ concerns. Hybrid vigor allowed breeders to improve yield, a complex quantitative trait that would have otherwise been difficult to steadily improve.
Among the surveyed farmers, the adoption of hybrids was the principal cause for landrace abandonment, and it was mentioned 18 times in focus groups and 11 times in the interviews (Table 4). Indeed, hybrids addressed some of the common issues farmers dealt with during maize cultivation. In farmers’ words, they preferred hybrids over landraces because of their higher yield by weight, shorter stature, lower incidence of lodging, greater resistance to pests and diseases, and to a lesser extent, the ability of hybrids to produce two cobs or tolerate higher planting densities. Nonetheless, farmers disliked the need to purchase hybrid seed every planting season and the considerable price they had to pay for the seed.
Changes in the maize cultivation regime
Agricultural extension service recommendations were transformed substantially with the introduction of maize hybrids, which we interpreted as a change in the scientific regime. These recommendations changed based on assessments undertaken by the National Agricultural Research Institute (INIFAP) in its experimental station in the municipality of Zacatepec, Morelos. Every year INIFAP evaluates hybrids and improved varieties for two of the agro-ecological zones in Morelos, dry tropical and sub-humid sub-tropical. Highest yielding cultivars are included in their maize cultivation guidelines. The cultivation system recommended for hybrids differed from that of the landraces. Farmers traditionally sowed landraces using three to five seeds per hole, leaving 1 m between holes. They applied natural fertilizers and controlled weeds mechanically using hand tools or animal traction. Instead, the technological package promoted during the Green Revolution included synthetic fertilizers, insecticides, herbicides and machinery, as well as improved seeds (Pichardo González 2006). INIFAP guidelines recommended higher planting densities for hybrids. Such densities increased from two seeds per hole every 50 cm in 1975 to a single seed every 17 cm in 2017 (INIA 1975; INIFAP 2017).
In three focus groups, the fact that landraces were not adapted to the new cultivation system was considered to be a cause for their abandonment (Table 4). Farmers observed that the substitution of mechanical weeding with chemical treatments increased lodging in landraces. Landraces in Morelos can reach up to 4 m high. The mounding up of soil at the base of the plants as part of mechanical weeding provided some necessary stability to landraces, but the denser planting arrangement recommended for hybrids complicated mechanical weeding. Farmers found that single-seed sowing meant less support for individual plants and that the recommended chemical fertilization overstimulated the production of green matter in landraces. This led to taller plants, further aggravating lodging. For farmers who abandoned animal traction, the height of the landraces became a problem: tractor implements would break the maize plants when they entered the field for the second weeding. Farmers who adopted the new practices often found it too costly or complicated to manage two cultivation systems simultaneously and, consequently, abandoned their landraces.
Farmers in one focus group and three interviewees observed that the more intensive cultivation system caused a reduction of natural soil fertility over the long term (Table 4). These farmers recalled that when they started applying chemical fertilizers they used a small dose per plant that was the volume of a bottle cap. However, they observed that a successful harvest now depended on a higher recommended fertilizer dose. These farmers noticed diminishing yields over time in their landraces as a result of poor soil fertility, and eventually abandoned these landraces.
Climatic macro-level changes favoring hybrids
A macro-level change in precipitation patterns reinforced the adoption of hybrids for farmers in two groups and in five interviews (Table 4). Farmers perceived that rains were abundant and regular some decades ago, while now they were scarce and erratically distributed. They recalled severe droughts around 1974 and 1982 consistently across municipalities. Farmers recalled losing most of their harvest those years, having to resort to the yellow maize that was brought to the community for consumption, instead of white maize. Based on these observations, farmers preferred hybrids because they found them to be more resistant to dry spells and drought than landraces.
Macro-level urbanization and market regime changes favoring hybrids
Macro-level population growth and the resulting urbanization fostered the emergence and consolidation of large urban markets. Farmers from Cuernavaca noticed a rapid expansion of the urbanized area after victims of the 1985 Mexico City earthquake relocated to Morelos. The urban population required a larger maize grain market, as maize is the primary staple in the Mexican diet. Within this market a sector specialized in tortilla production, both hand- and machine-made, emerged. Farmers recalled how around the 1960s every household in town was still cultivating and grinding its own maize and making tortillas. Eventually town mills emerged where people could grind maize to make tortillas at home. Later, tortillerías emerged that would sell the final product. Some focus groups recalled the first tortillerías in the 1990s, while others since the 1970s.
Market regime changes had two simultaneous and converging effects on farmers’ families. As producers, farmers’ focus shifted from satisfying household needs and selling surpluses to neighbors, to satisfying market requirements. As consumers, farmers found in tortillerías a convenient alternative that reduced women’s workload. More urban households also meant more maize consumption, but this was in the form of manufactured tortillas. Thus, the characteristics favored by tortilla manufacturers became more important than the consumption characteristics in which landraces outperformed hybrids. Farmers referred to these changes repeatedly (eight times in the groups and six in the interviews, Table 4), explaining that hybrids were more marketable than landraces, that buyers preferred hybrids or that farmers often resorted to manufactured tortillas, even though they consistently stated that landraces made tastier, sweeter and softer tortillas.
These transformations correspond not only to changes in user practices within grain markets but also to changes in the technological regime of grain processing. Tortilla manufacturers noticed that hybrids outperformed some landraces in terms of kilograms of dough and/or number of tortillas per kilogram of grain processed. Consequently, they started specifically demanding hybrids. Industrial maize processing also required grain hardness and size characteristics that hybrids satisfied better. In addition, while neighbors used to buy maize by volume, grain markets started buying maize by weight. The importance of yield by weight, a trait in which hybrids outperformed landraces, increased as a result.
Hybrid maize adoption spread in other parts of Mexico as well. In the northern states, hybrid adoption was widespread and achieved economies of scale (Donnet et al. 2012). Soon farmers from Morelos had to compete with hybrid maize coming from other states at lower prices. The Morelos road infrastructure network, well developed since the 1970s as an entry/exit point to/from Mexico City, facilitated this process (SPP 1981; INEGI 2016). With lower prices and a more competitive market, farmers in two groups and four interviewees expressed that it was no longer possible for them to offset the labor cost to produce landraces or even maize. In one focus group, farmers directly referred to the interstate competition (Table 4).
An urban market for fresh corn-on-the cob (elotes) developed in parallel with the grain market. This was apparent in the emergence of fresh corn-on-the-cob stands as a popular form of street food. Farmers who could access irrigation found this market attractive because fresh cobs could be sold by the ear, instead of by weight or volume. By 2008 more than 2/3 of the 9044 irrigated maize hectares in Morelos were harvested as fresh cobs (INIFAP 2017). Stand owners demanded compact tight-rowed ears that require fewer ingredients to season traditionally, in addition to a year-round supply. Breeders satisfied this demand by developing specific fresh corn-on-the-cob hybrids. Farmers in three groups and two interviews explained that middlemen often requested them to grow these hybrids to guarantee the purchase, making hybrid adoption obligatory (Table 4).
Macro-level and market regime changes favoring Ancho
At the macro level, population increase and urbanization fostered another important market regime change: the development of a market for Ancho. Ancho landrace has characteristic wide, starchy kernels that pop when boiled. Buyers offer a premium price for Ancho because it is used in pozole: a hominy, meat and chili pepper soup. The popularity of pozole for celebrations in Mexican households has given this market considerable potential. Price premiums increased with the development of a size-based seed classification system, embryo removal methods to facilitate popping and a precooked maize processing industry. Demand increased with the development of other industrial applications for the grains’ high starch content. Pest incidence limits the production of such high starch grains in warm areas (Romero, F. J., personal communication, September 12, 2017). These factors together favored the production of Ancho landrace in temperate areas with optimum growing conditions. This might explain the observed conservation of Ancho accessions (Table 2) showing a clear non-random distribution in the municipalities of Totolapan, Tlayacapan, Yecapixtla and Atlatlahucan. For three groups and six interviewees the preference for Ancho limited hybrid adoption but also limited the conservation of other landraces over which Ancho was preferred (Table 4).
Policy and cultural regime changes favoring hybrids
Changes in two other regimes, political and cultural, further reinforced hybrid adoption. Two groups and 12 interviewees highlighted a policy change: the implementation of subsidies for hybrid seeds (Table 4). As part of the national strategy for maize self-sufficiency, the Secretary of Agriculture has allocated resources to support hybrid adoption through state governments. In Morelos these subsidies benefited 871 maize producers with inputs for one to three hectares each in 2017 alone (SAGARPA 2017). Farmers mentioned they became interested in hybrids after receiving financial subsidies or technological packages from government authorities. Additionally, some of these subsidies were linked to transformations in other sectors. In Yautepec farmers recalled that hybrids were promoted in the 1990s through a program coordinating a transition from sugar cane to maize after the closure of the Oacalco sugar mill.
The way farmers perceived maize hybrids changed their cultural regime and encouraged hybrid adoption over landraces. A positive connotation has been embedded in the language used by breeders and the government surrounding the notions of improved varieties and strategies for agricultural modernization. Farmers in two focus groups stated that because they perceived themselves as innovative they were interested in adopting hybrids (Table 4). An interviewee who adopted hybrids expressed that he still perceived people cultivating landraces and using traditional cultivation methods as outdated. Thus the positive associations of hybrids with modernization and forward thinking favored the abandonment of landraces in these cases.
User practice changes affecting specific landraces
Changes in user practices unrelated to hybrids also affected the cultivation of certain landraces. In Puente de Ixtla farmers used to cultivate Delgado because of its high yield by volume. They preferred this landrace to produce the eight sacks of maize required to pay for the rent of an oxen yoke. In the 1980s Lauro Ortega, one of the most popular governors of Morelos, distributed mules to farmers in the municipality. Farmers abandoned the cultivation of Delgado when they no longer had to pay for the rent for a yoke.
Farmers in one group and one interviewee abandoned black and red landraces (Negro and Rojo) when town mills appeared (Table 4). This happened because some users repeatedly expressed their dissatisfaction when leftover dough of the colored landraces from the previous user would mix with their white dough. Another family abandoned these landraces in order to avoid crosspollination with white landraces in the field when they reduced the area planted with maize. Because buyers prefer white maize for tortillas, grains with mixed colors would have been harder to sell. This represented the loss of valuable germplasm. Farmers in two groups and one interviewee recognized that, while black and red landraces from other states are widely available as grain in the markets, local varieties taste better and are better adapted to local soils and climates.
Alternative markets affecting maize
The expansion of other agricultural markets affected the cultivation of landraces by reducing the preference for maize cultivation. While investments in irrigation in Morelos supported an increase in the total cultivated surface from 124,564 to 130,345 hectares between 1970 and 2012 (Barseló Oliete 1982; INEGI 2013b), maize cultivation decreased from 50,000 to 35,142 hectares (INIA 1975; INIFAP 2017). Morelos has supplied agricultural products to the vast markets of Mexico City since pre-colonial times (Ávila Sánchez 2002). Whenever the soil and climate in Morelos have proven suitable for highly demanded crops, these have disseminated quickly. Farmers referred to the tomato boom in Atlatlahucan and Totolpan between the 1960s and 1980s. Government subsidies increased sorghum cultivation for cattle feed since the 1970s in warmer municipalities, including among others Amacuzac, Temixco and Zacualpan. Fruit trees disseminated in Tetela del Volcán since the 1980s after governor Lauro Ortega introduced an irrigation project. Nopal (Opuntia cacti) became popular in Tlalnepantla and Tlayacapan since the 1990s. In these locations crop substitution was the predominant cause for farmers abandoning maize landraces (Table 4).
Macro-level changes affecting maize
Industrialization was another macro-level process that affected maize cultivation. The remaining agriculture in municipalities of the Cuernavaca Valley was reoriented mostly to peri-urban crops such as vegetables and flowers. This transformation was so strong that maize cultivation had effectively disappeared from the main towns in these municipalities, and we had to relocate our focus groups to smaller towns. Industrialization intensified population growth and urbanization. Farmers in two groups and six interviews explained that they decided to abandon maize when their plots ended up surrounded by urban zones, because passers-by would steal a significant harvest share as fresh cobs (Table 4).
Policy and cultural regimes changes affecting maize
Land use change was intensified when in 1992 the government modified Article 27 of the Constitution and emitted a New Agrarian Law (SEGOB 1992). Land ownership was previously recognized collectively and ejido membership, land use and land transactions were restricted in favor of the collective interest of ejido members.Footnote 6 Instead, the new law and its operational program PROCEDE favored market efficiency. They opened up the possibility for members to obtain individual plot certificates and sell their plots to agents outside the ejidos (Bouquet 1996). Ejidos could choose to participate in the certification program collectively, upon approval of the general assembly. In the study area, certification favored plot sales and often resulted in urbanization.Footnote 7 Focus group participants in Atlatlahucan explained that tomato growers, unable to repay their credits after bad years, sold their plots to developers or lost them to the bank. Ejidos like Nepopualco in the municipality of Totolapan chose not to participate in PROCEDE to retain their cohesion. Coincidentally, the three families from Nepopualco who donated Ancho maize in 1967 were cultivating Ancho of the same and different seed lots in 2017.
A cultural change derived from urban transformations further affected maize cultivation. People’s interest in agriculture decreased with the possibility of obtaining an urban job. The urban lifestyle was often perceived as superior in rural areas. In three groups and five interviews farmers explained how they struggled to foster enthusiasm for agriculture in their grandchildren (Table 4). Moreover, they explained how it had become difficult to find sufficient seasonal fieldworkers. Fieldworkers were demanding a shorter workday and a compensation of MXN$200/day (approximately US$10), which farmers found unreasonably high.
Reduction of the average plot size as a result of land division among descendants also increased the interest in urban jobs. In 1970 there were 8118 ejido members reported for 347,623 hectares of arable land in Morelos (Barseló Oliete 1982). By 2007 ejido surface area increased to 396,526 hectares, but the number of members increased to 64,157 (INEGI 2014). As a result, the average area allocated to each member decreased by 86%, from 43 to six hectares. Whenever they were not interested in agriculture or did not inherit land, farmers’ descendants found a permanent non-agricultural occupation. To limit land division, some farmers chose not to transfer land to their daughters. They explained that women were expected to obtain land or income from their husband’s side. Often, even the most likely successor had to find a temporary off-farm job until the head farmer of the family retired.
In Tlalnepantla and Totolapan, the absence of a younger generation to take over the plots affected maize landrace cultivation (Table 4). As farmers aged, they abandoned maize cultivation in their most distant plots in the mountains. These plots were harder to cultivate because of their cold and humid conditions. Landraces such as Criollo and Del Monte maize (meaning “from the mountains”) were adapted to these plots. They were planted earlier in the year, in February or March, and relied on residual soil moisture until the rains arrived. Older farmers abandoned these landraces either by introducing less labor-intensive crops such as forages, or abandoning the plots altogether.
Resistance against the transition
Interviewees explained how resistance or barriers against the socio-technical transition manifested within individual families. Family members could disagree on which decisions to take about their landrace. In these cases, they had to wait for specific moments to implement their decisions. Farmers emphasized the importance of these moments among the reasons for landrace abandonment in their families.
It was more common for older farmers to resist the change, although we found cases of both generations resisting. In 12 interviews younger farmers wanted to abandon landraces, but older farmers did not. Older farmers manifested their resistance by cultivating their landrace in a small plot until they were no longer able to farm. Young farmers abandoned large-scale landrace cultivation when they took over farm management, and then abandoned landrace cultivation completely when the older farmers passed away (see example in Fig. 4 and details in Online Resource 4, Fig. 1). In four other interviews, older farmers wanted to change their landrace even though their children preferred it (Online Resource 4, Fig. 2). Thus, farmers abandoned their landraces during their children’s temporary off-farm occupation. In one interview, landrace abandonment was related to gender dynamics (Online Resource 4, Fig. 3). This young female farmer had to abandon her landrace once she could not take over the labor-intensive cultivation of her father’s rocky hillside plots.
In the winter of 2016/2017 we delivered samples from the ex situ collection to interested interviewees and focus group participants. During interviews, 21 families who had lost their seed lots expressed interest in recovering them because of the personal value they attributed to their father, mother or grandfather’s seeds. Nine other families wanted to recover their accessions for their productive value. They recalled liking their landrace but had been unable to obtain seeds in the market. All families were surprised to find out that their seeds had been conserved elsewhere and could be retrieved.