Genome Plasticity in Buckwheat

Abstract

Plasticity is the ability of a plant genotype to respond to different environmental conditions by producing different phenotypes. Classic examples of phenotypic plasticity in plants include response of leaves to sun, heterophylly , environmental control of cleistogamy, responses to herbivory, inter- and intra- specific competition, allelopathy. True plastic responses to variations in environment have just as firm a genetic basis as other plant characters. As a parameter which is determined by those genetic systems that control development, plasticity can be considered as an epigenetic phenomenon. Thus, plastic responses represent changes in ‘typical’ developmental sequences due to the interaction of the organism’s genotype with the environment. Even though the diversity of genetic resources is fundamental for ecosystem functioning, sustainable agricultural production and attainment of food and nutritional security, yet only a few crop species are utilized for food production throughout the world. Further, erosion of genetic resources is having serious consequences, both on the genetic vulnerability of crops to changes in environmental factors as well as in their plasticity to respond to changes in climate or agricultural practices. Since a crop’s ability to tolerate the vagaries of environment is dependent on a complex combination of responses and mechanisms, an understanding of morphological, physiological, and genetic mechanisms involved in the responses of these crops assumes significance. As a source of agronomic traits for breeding and adaptability to changing environments genetic diversity in agricultural crops have tangible values. However, the shrinkage of agricultural basket due to “agricultural simplification,” is having a significant impact on sustainability of farm agroecosystems. Of particular concern, the cultivation of traditional crops has declined and continues to decline globally, yet such crops offer greater genetic diversity, and have the potential to improve food and nutritional security. Among these, the International Plant Genetic Resources Institute (IPGRI) and Consultative Group on International Agriculture (CGIAR) have identified buckwheat (Fagopyrum spp.), grain amaranth (Amaranthus spp.), and (Chenopodium spp.) as crops of potential for future. Common buckwheat (Fagopyrum esculentum Moench), a diploid (2n = 16) annual crop plant, is widely cultivated in Asia, Europe and America. Due to short growth span, capability to grow at high altitudes and the high-quality protein content of its grains, it is an important crop in mountainous regions of India, China, Russia, Ukraine, Kazakhstan, parts of Eastern Europe, Canada, Japan, Korea, and Nepal. The plant is known to have three viz. summer, intermediate, and late summer ecotypes. While the late-summer ecotypes are low altitude cultivars, the summer ecotypes are cultivated at high altitudes. The summer ecotypes have been suggested to have been evolved from late summer ecotypes through selection of early flowering plants under long-day conditions; the selection being a part of the domestication process in buckwheat for climatic adaptation.