半姊妹与全姊妹轮回选择对玉米沈综（旅）C_1群体改良效果的研究

应用半姊妹轮回选择和全姊妹轮回选择两种方案对玉米沈综（旅）Ｃ_１群体进行改良，根据调查、考种结果对各群体产量及性状进行分析。结果表明，两种方案对群体的改良是有效的，半姊妹、全姊妹改良群体分别比沈综Ｃ_０群体产量提高２８．７％和２３．７％，达到极显著（０．０１）和显著（０．０５）差异水平，ＨＣ_２、ＦＣ_２两群体间产量差异没达到统计上的显著水平，半姊妹改良方案较全姊妹改良方案的实际遗传增益大，二者分别是１１．７２％和７．３７％，其预期遗传增益分别为３．４２％和４．２７％。相关、通径分析表明，不同群体的农艺性状与单株产量的相关程度有差异，其贡献大小也不尽相同，两种轮回选择方法，尤其是半姊妹轮回选择导致群体的遗传变异更趋狭窄。

Study on Improvement Effect of Half-sib and Full-sib Recurrent Selection on Shenzong(lu)c_1 Population in Maize

HALF-SiB recurrent selection and full-sib recurrent selection were used for improving base population shenzong(Lu)C1.Two kinds of improved population HC2 and FC2 were obtained,and population C1 and population C0 were planted in same experiment togather.Yield and agronomic traits were analysed through investigating result.The results showed that two recurrent selection programs yield in a population yielded good results. The yield of grain in improved population (HC2 and FC2) were higher than that of base population (C0)28.7% and 23.7% respectively.The differences were significant on 0.01 and 0.05 level in statistics.There are no significant differences of yield between HC2 and FC2 Genetic gain in half-sib family is higher than that of full-sib family, they are 11.72% and 7.37% respectively,their expected value are 3.42% and 4.27 respectively.The correlation and path analysis showed that the correlation between agronomic traits and yield per plant vary in ddifferent population,the size of contribution in agronomic traits to yield are also different.The range of genetic variability changed to be narrow because of two selection programs expecially half-sib selection.