30余年来北部冬麦区小麦品种产量改良遗传进展

采用1965年以来北部冬麦区育成的10个主栽品种，在水、肥供应充足、病、虫、倒伏得到有效控制条件下，连续两年共进行4个点次试验；同时对1B/1R易位系和矮秆基因进行分子鉴定。结果表明，品种产量年遗传进展为64.63 kg hm^-2 或1.20%，其较大幅度的提高出现在1980年丰抗号品种育成时期。丰抗2号和丰抗8号是该地区最早育成的含有1B/1R染色体和Rht-D1b矮秆基因的品种。主要农艺性状演变的总趋势是抽穗期提前、株高显著降低、生物学产量基本保持稳定、单位面积穗数减少、每穗粒数有所增加、千粒重和收获指数大幅度提高，其年遗传进展分别为－0.1%、－0.70%、0.35%、－0.50%、0.63%、1.12%和0.79%。通过减少不孕小穗和小花数来增加每穗粒数，通过提高灌浆速率来提高千粒重，再把高穗粒重与较多的单位面积穗数结合在一起，是北部冬麦区进一步提高产量的重要途径。

Genetic Gain of Wheat Breeding for Yield in Northern Winter Wheat Zone over 30 Years

Knowledge on genetic gain of yield potential and its associated traits is essential for understanding yield-limiting factors and developing strategies for future variety improvement.Yield potential trials,comprised of 10 landmark and newly released wheat cultivars(Triticum aestivum L.) from Beijing,were conducted,using a complete randomised block design with three replicates,under controlled environment during 20012002 and 20022003 seasons.Molecular markers were used to detect the presence of dwarfing genes and the 1B/1R translocation.The result showed that genetic gain in yield was 64.63 kg ha-1 year-1 or 1.20% per year.The breakthrough on yield plateau occurred at the period of release of Fengkang cultivars in 1980.Fengkang 2 and Fengkang 8 were the first cultivars carrying 1B/1R and Rht-D1b released in Beijing.Yield genetic gain was slowed down after 1980.Newly released cultivars were characterized by early heading,reduced plant height,decrease of spikes per square meter,slight increase of kernels per spike,remarkable increase of thousand kernel weight and harvest index, with annual genetic gains of-0.10%,-0.70%,0.35%,-0.50%,0.63%,1.12%,and 0.79%,respectively.Increasing the number of kernels per spike by reducing the number of sterile spikelets per spike and reducing the number of sterile florets per spikelet,increasing thousand kernel weight by increasing the rate of grain filling,then combining greater weight of grains per spike with higher number of spikes per squire meter,is one of the best approaches in breeding for further yield increase.