大粒水稻之遺傳研究 I. 抽穗期、株高、每株穗數及一穗頴花數之遺傳

Abstract

以包括親本與正反交組合之9 × 9 全互交F1材料探討大粒水稻主要性狀之遺傳。抽穗期、株高、每株穗數及一穗頴花數等4個重要農藝性狀親本間遺傳變異均極大，此變異係由累加性與顯性效應所引起。除抽穗期外，餘3性狀之累加性效應均遠大於顯性效應。4個重要農藝性狀之狹義遺傳率均頗高，指出4性狀之表現型變異主由累加性效應控制。4個重要農藝性狀均發現有細胞質效應。經由迥歸與變方分析估得4個性狀之顯性程度除抽德期為完全顯性外，餘均為部分或不完全顯性，正負等位基因之頻度在親本間之分布不等，且顯性基因多於隱性基因數。而藉迴歸圖析及親本顯性次序之判定，抽穗期早者為顯性，餘3性狀之顯性方向是為雙方向。 The inheritance of main characters of larger kernel size of rice were studied by means of a 9 × 9 diallel crosses including parents and reciprocal crosses. The genetic variations of four agronomic traits, heading date, plant height, panicle number and spikelet number, were significant among the parents. Both additive and dominance effects were important for all four agronomic traits. Furthermore, additive effects were significantly larger than dominance effects for all agronomic traits evaluated except for heading date. Estimated heritabilities for all agronomic traits were very high indicating that a major portion of phenotypic variability was controlled by additive effects. Maternal effects existed in all four agronomic traits. Degrees of dominance for four agronomic traits estimated by graphic and variance analyses showed partial or incomplete dominance except that heading date was complete dominance. The average frequencies of positive and negative alleles in parents were not equal and the number of dominant genes exceeded recessive genes for four agronomic traits. Directions of dominance evaluated by regression plotting and correlation coefficient between Yr and (Wr+Vr) were toward early maturity for heading date and ambidirections for the others agronomic traits.