云南稻种耐冷性状的杂种优势及配合力分析

Heterosis and combining ability of cold tolerance characters for rice in Yunnan

用Griffing II等法对5个不同耐冷级别的标准品种及其配制的14个杂交、回交组合F1 进行穗部花药、颖壳和结实率等耐冷性状的细胞质效应、杂种优势和配合力分析表明: (1) 强、弱耐冷性状的影响是母本基因型和细胞质效应在子代的直接表达及母子物质交换效应综合作用的结果。(2) 地理远缘和耐冷性差异较大的品种间的杂交, 后代杂种优势较强, 尤其是丽粳2号、合系4 号与十和田间的杂交组合,无论是花药大小还是结实率均较高;丽粳2号药药大小与结实率性状的GCA明显比十和田、大理早籼高, 丽粳2号可作为云南稻种耐冷性育种的骨干亲本和培育近等基因系(NIL) 较好的遗传材料, (3) 不同组合耐冷性状的SCA差异较大, 昆明小白谷与大理早籼杂交SCA较高,GCA较低的大理早籼、十和田与丽粳2号杂交SCA也较高。(4) 水稻耐冷性强弱不仅与花药大小有关, 还与颖壳长增量有关, 可望提出耐冷性动态鉴定体系。

crosses and backcrosses from five standard rice cultivars with different grades of cold tolerance were used to study the cytoplasm effect,heterosis and combining ability of F l in cold tolerance characters (anther,chaff and setting percentage etc.)using the method put forward by Griffing(1956).The results showed as follows:(1)In the cold tolerance characters of the crosses between the strong and weak cold tolerance varieties, there were the cytoplasmic nuclear interaction,its influence was the comprehensive effect results of the direct expression of the maternal genotype, cytoplasm effect on their progeny,and the material change effect between the female parent with strong cold tolerance;(2)The geographically wide crosses of cultivars different in cold tolerance showed higher hetrosis,e.g.Lijing No 2×Hexi No 4 and LijingNo 2×Toawda,on the anther size and setting percentage. GCA of the anther and setting percentage in Lijing No 2 might be higher than Toawda,Dalizaoxian; Lijing No 2 is used as the backbone parent of cold tolerance and the genetic material to select the near isogenic lines(NIL).(3)There existed great difference in SCA between combinations, SCA was very high in the cross Kunmingxiaobaigu×Dalizaoxian,SCA of the Combinations from Lijing No 2 crossed with lower GCA cultivars (Dalizaoxian,Toawda)were also very high.(4)Rice cold tolerance is not only connected with the anther size,but also with the increment of chaff length.For futher stndy, a dynamic method in cold tolerance identification should be propoeed.