Analysis of the factors relating to vanetal differences in yielding ability and yearly variations in grain yield of nee bred for cold climate regions

于2001 ~ 2003年进行了12个新品种（系）与日本东北地区广泛栽培的秋田小町和一目播的产量及产量构成因素的田间试验。并对影响产量的干物质生产和分配以及品种间产量年际变化的因素进行了分析。1）2001年粮食产量为765 ~ 908 g/m2<-2>，2002年为700 ~ 770 g/m2<-2>，2003年为230 ~ 660 g/<-2>m2。2003年7月下旬至7月下旬的低温和太阳辐射造成小穗不育，导致籽粒成熟率降低，导致各品种籽粒产量下降。2）除2003年外，5年平均产量在秋田小町735 g m^~冲<-2>入817 g m^之间<-2>，产量差异约为80 g m^<-2>（11%）。秋田小町和花野内的低产量是因为尽管PRG高，但水槽尺寸小。福比木、冲入、门小稻和岩南7号的高产主要是由于库容量大和PRG高。3）在早熟期，各品种穗重的增加量远大于总干重的增加量。茎、叶鞘重量下降幅度较大的品种，其PRG值往往高于茎、叶鞘重量下降幅度较小的品种。4）长秆品种的倒伏指数大于短秆品种。一些新品种的截面指数和弯曲应力较大，其断裂力矩大于推广品种。

Field experiments were carried out in 2001〜2003 to compare the yield and yield components of 12 new cultivars or lines with those of Akitakomachi and Hitomebore, the two widely-cultivated cultivars in the Tohoku region of Japan. Dry matter production and partitioning related to yield, and factors causing the yearly variation in yield among cultivars were also elucidated. The obtained results are shown as follows1)The grain yield ranged from 765 to 908 g m^<-2> in 2001, from 700 to 770 g m^<-2> in 2002 and from 230 to 660 g m^<-2> us 2003. Low temperature and solar radiation during the end of Jane to the end of July in 2003 caused spikelet sterilization, resulting in the low percentage of ripened grains(PRG), and subsequently reduced grain yield in all cultivars. Yearly variation in grain yield was often smaller in the high cool resistant cultivars(Hananomai, Hatajirushi and Hitomebore) than in the low cool resistant ones because of a lower percentage of sterilized spikelets and the higher yield in the former cultivars in 2003.2)The average yield in 5 years, except in 2003, ranged from 735 g m^<-2> in Akitakomachi to 817 g m^<-2> in Okiniiri, and the yield difference was about 80 g m^<-2>(11%). The low yield in Akitakomachi and Hananomai was because of a small sink size despite a high PRG. On the other hand, the high yield in Fukuhibiki, Okiniiri, Menkoina and Iwanan 7 was mainly caused by a large sink size and a high PRG.3)In the early ripening stage, the increase of panicle weight was much greater than that of total dry weight in all cultivars. Cultivars with a larger decrease in stem and leaf sheath weight often had a higher PRG than those with a smaller decrease in stem and leaf sheath weight.4)Lodging index was larger in the long-culm cultivars than in the short-culm ones. The breaking moment of a culm was larger in some new cultivars than in the widely cultivated ones because of a larger cross section index and bending stress in the former.