水稻强优势恢复系9311粒重的诱变改良

通过EMS诱变恢复系9311种子筛选到了大粒突变体M316。M316整精米的粒长由原来的6．9mm增加到8．0mm，增幅达15．9％，千粒重由原来31g提高到35．6g，增幅达14．8％，但着粒密度明显变稀，由原来的6．77粒／cm减少到5．61粒／cm，减幅达17．1％，因此单株产量比原品种减产8．7％。并通过M2、M3、M4代该性状分离表现，初步推测该突变为隐性突变。有趣的是，该突变体与培矮64s、粤泰A、广占63s分别配制的F1，与原来组合两优培九、粤优938、丰两优1号相比，不仅千粒重有明显增加，穗长和每穗颖花数有不同程度提高，而着粒密度和其它主要性状未发生劣变，因而单株产量有不同程度提高。说明该突变体在粒重增加的同时，配合力得到显著改良。

Mutagenic Improvement of Grain Weight of Superior Heterosis Rice Restoring Line 9311

A grain size mutant of restoring line 9311, M316, was identified by EMS treatment. It's grain length and 1000-grain weight was increased from 6.9mm to 8.0mm and 31g to 35.6g, with an increased rate of 15.9% and 14.8%, respectively. However, the seed density of M316 was significantly decreased from 6.77 seeds/c m to 5.61 seeds/cm, with a decrease rate of 17.1%. As a result of these factors, single plant yield was decreased by 8.7%. Phenotype segregation observation of this trait in generations M2, M3 and M4 indicated that this was an accessive mut ation. Interestingly, compared with the three original hybrids Liangyoupeijiu, Y ueyou 938 and Fengliangyou No.1, the F1 hybids between the mutant and sterile li nes Pei'ai 64s, Yuetai A, and Guangzhan 63s was significantly improved in 1000-g rain weight, panicle length, and number of spikelets per panicle, but the seed d ensity and other important traits were not decreased. Therefore, single plant yi eld of the new hybrids were increased in varying degrees, indicating that the mu tant were obviously improved in both the combining ability and grain weight.