小麦品种间不同穗粒位粒数与粒重的变异

用不同穗型的５个小麦品种对单穗不同穗段的结实粒数和粒重的变异进行了研究。结果表明，不同穗型的小麦品种各穗段的结实粒数和粒重均有显著差异，一般以Ｍ１穗段的粒数最多和粒重最高，Ｕ２段的粒数最少和粒重最低，Ｍ２、Ｌ、Ｕ１则居中，但少粒型品种７９－２８１２的这两个性状在穗段的分布则小有差异。形成这种变异的原因主要由于顶小穗出现的早迟所致。在单穗内以Ｌ、Ｍ１、Ｍ２三穗段的粒数和粒重占绝对优势。在一个小穗中，以基部籽粒最重，随粒位上升而粒重递减，顶端粒最轻。结实５ｋ７粒的小穗以第３粒最重；结实３ｋ４粒者以第２粒最重

VARIATION OF GRIN WEIGHT AND GRAIN SET BETWEEN EAR SECTIONS IN DIFFERENT EAR-TYPE OF WHEAT GENETYPES

A study of variation of grain weight and grain set between ear sections in different ear-type of wheat genotype was investigated in 1985-1986 and 1978-1988. Results showed that grain set and grain weight in different ear sections of the five different ear-type of wheat genoltypes were considerably different. In general,the maximum of grain wightand grain numbers were observed in ear section M 1 and the minimum in section U 2 ,section M 2 ,L and U 1 between the two extreems. Whereas, the ranking of section in cultivar 79-2812 displayedcertain diffrence. Both the two characters of theLM 1 M 2 within ear had absolute dominance.Within spikelets the weight of firstand second grain was the heaviest,the grain weight of more distal grains tendedto be on the decrease.