提前割除父本对杂交水稻制种产量和种子质量的影响

为研究赶粉结束后提前割除父本对杂交水稻制种产量和种子质量的影响,以‘广8优165’和‘宜优673’两个杂交水稻品种的双亲作为试验材料开展了比较试验。研究发现,赶粉结束后提前割除父本可显著提高杂交水稻制种结实率,增加千粒重,提高种子发芽率,降低易裂颖品种的裂颖率,利于在遭遇不利天气时择机抢收和规避机械混杂,可提高杂交水稻制种产量和增加制种效益。研究证明,赶粉结束后提前割除父本可提升种子质量,增产又增收,是值得推广的一项农艺措施。

The Combining Ability and Genetic Parameters of Yield per Plant and Other Characters of 11 Maize Inbred Lines

The combining ability, heritability and reciprocal effects of yield per plant and other characters of maize inbred lines were studied to provide a basis for the selection of maize inbred lines and the combination of maize hybrids. Using 11 maize inbred lines as test materials, we matched 110 combinations according to Griffing III complete diallel hybridization method. Seven phenotypic characters, i.e., yield per plant, plant height, ear height, branch number and spindle length of tassel, silking and anthesis stages of the inbred lines were observed, and the general combining ability (GCA), special combining ability (SCA), reciprocal effects (REC), broad- sense heritability (H2B) and narrow- sense heritability (H2N) of the above characters were estimated. The results showed that both GCA and SCA of all the tested traits were significantly different except the SCA of spindle length of tassel. The GCA of yield per plant of JZ3 and JZ6 inbred lines was significantly positive. Two pairs of the combinations, JZ9×JZ2 and JZ2×JZ9, JZ6×JZ3 and JZ3×JZ6, had the largest positive SCA effect values of 40.68 g and 35.24 g, respectively. The REC of yield per plant had significant difference; however, some inbred lines had large variances in the REC. The H2B of the seven characters in the descending order was tassel branching number, plant height, the anthesis stage, ear height, the silking stage, yield per plant, and spindle length of tassel. The H2N, ranging from big to small was tassel branching, plant height, ear height, the anthesis stage, spindle length of tassel, silking stage, and yield per plant. The results suggest that the dominant genetic variance accounts for the largest proportion, H2N of yield per plant is the smallest; therefore, the yield per plant is easy to be affected by environmental conditions and suitable for selection in later generations. Because of the significant REC in yield per plant, the way of crossing in some inbred lines need to be strictly controlled.