Studies On The Heterosis And Genetic Effect Of Major Economic Traits For Upland Cotton

Taking6upland cotton varieties which has stable characters as test material, Using the way of complete diallel cross to combine30cross combination. to research the heterosis、genetic effects、correlation and combining ability effect of yield and fiber traits for upland cotton by the test data of F1、F2. To understand the genetic regularity of main economic characters for upland cotton. It will provide the theory reference and new test data for breeding varieties and heterosis utilization in future. The result and analysis of this test are as follow:1. Compared with other cross combination, Z23、Z36、Z42and Z45had shorter full growth period, meanwhile the flowering stage and boll opening stage of Z23、 Z36、Z42and Z45are relatively concentrated. they are typical combination which developed quickly in middle、later stage. the full growth period of the30cross combination were concentrated on117～122d in normal environment, belong to middle maturing variety.2.Compared with yield and fiber quality of the F1and F2, in comprehensive characters, Z63>Z64>Z42are highest yield and best fiber quality among30cross combination. Z51(145.7kg/mu)has higher yield, but its fiber quality is general. Z62(162.7kg/mu) has higher yield, but its fiber quality is bad. Z13and Z43have better fiber quality,but it have middle yield.3.In genetic effect and correlation, the genetic effect of the fruit branch、lint percentage、fiber length、uniformity and micronaire are main of dominant effect, the genetic effect of the strength、ginned cotton and plant height are main of additive effect.Besides, the GCV%of those traits are low of10%.In the analysis of correlation and correlation degree, the correlation of ginned cotton and boll number is very significantly positive correlated.Between fiber length and uniformity、elongation percentage、fiber strength are positive correlation, but it is negative correlation with Mic value(rp=-0.09).4.Studies on combining ability effect and heterosis,the cross combination that their yield and fiber quality are excellent have higher SCA and GCA of parents, such as Z63、Z64、Z43and so on. For most combination, If combination’s parents have lower GCA, their yield and fibre quality are poorer than other combination, even if they have higher SCA. So GCA is important for Fi. we should selecte cross combination which has a distant genetic relationship and their parents has high GCA effect in yield and fiber quality.5. Conclusively, in the yield component factors of cotton, the GCA of P2and P6are best among6parents, lint percentage、seed cotton and lint are positive; In fiber traits, the GCA of P3and P4are best among6parents, fiber length、uniformity and fiber strength are positive.