杂交粳稻二代利用的研究

<正> 几年来,杂交粳稻在我国北方迅速推广种植,对提高水稻产量起着积极作用,为我国北方水稻生产开创了一条新的途径。但是,种植杂交水稻需要年年制种,这样供种不好计划,例如制种过多,一则是用不完,二则因隔年种子往往保存不妥善,造成发芽率降低;若制种少了,则又不够用。为此,我们试图研究一个合理的解决办法。

A STUDY ON THE USE OF F_2HYBRID IN KENG RICE HYBRIDIZATION

The use of F_2 hybrid in keng rica(round-grainad nonglutinous rice) hybridization is one of the important problems in the production of rice.In recent years,we have studied this problem.According to the result of the experments in 1980—1981,a preliminary conclusion has been drawn as follows: Ⅰ.The use of F_2 hybrid cannot be completely negated,but it can be used only on a definite condition,viz,in the definite district when seed of F_1 hybrid is insufficient.In some groups(such as Liyou 57,)seed of F_2 hybrid may act as the supplement seed. 2.Most F_2 plants of gametophitic—sterile crosses can normally blossom and bear fruit.some others prove to be sterile,but they only make up 1—2% ofthe total. 3.Since the sterility for sporophytic crosses of groupe F_2 is much greater (The highest account for 33%).Therefore its F_2 hybrid cannot be used. 4.Comparing the essential economic characters of F_1 and F_2 hybrid,it can be seen that the height of the plants,grain weight per plant,fertile grain number per ear and ear number per plant,F_1 hybrid is superior to F_2 hybrid.The grain number per ear of some crosses of F_1 hybrid is obviouslx greater than F_2 hybrid.Percentage of withered kernels of some crosses of F_2 hybrid is higher than that of F_1 hybrid.Hence the heterosis of F_1 hybrid is stronger than that of F_2 hybrid,and its output is higher. 5.In concentrated rice-growing area,those production teams that have some difficulties in isolation of seed production of Li yu 57 may bear seed in neighbour productive cropland of Liyu 57.