Reproductive growth inLolium 1. Evaluation of genetic differences within an established variety by means of a diallel cross
A genetic evaluation of S23 perennial ryegrass has been made by means of a 6 × 6 diallel cross. The characters studied were those associated with seminal reproduction and included seed yield and several of its primary components.
The pattern of variation between the parents indicated a mainly additive system, itema of the Hayman analysis being significant for yield and all the other characters. Maternal effects were not a constant feature, but were evident for seed yield, plant weight and spikelet numbers/inflorescence. Dominance was a prevalent feature and invariably acted in the direction of the greater expression of the character.
While a high level of incompatibility was evident from the paucity of seed setting on selfing, the variation between progeny yields following open pollination gave a range from the highly acceptable levels of commercial production to very low uneconomic levels. The results indicate that improvement in seed yield is feasible by breeding even though in this variety selection pressure has tended towards a restriction of variability for essentially agronomic features.
KeywordsSelection Pressure Variety Selection Seed Yield Seed Setting Prevalent Feature
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