Analysis of Fruit Length Using Mixed Major Gene and Polygene Inheritance Model in Summer Squash

[Objective]The aim was to provide scientific basis for breeding on the fruit length of summer squash.[Method]Inheritance of the fruit length of summer squash in P1,P2,F1,B1,B2 and F2 from two crosses q-1 ×23-4G（cross 1） and q-1 ×A-7（cross 2） was investigated by the mixed major gene and polygene inheritance model of quantitative traits.[Result]The results showed that the fruit length was controlled by D2 model;Genetic effect of fruit length of cross 1 was mainly additive effect,but genetic effect of fruit length of cross 2 was mainly dominant effect.Heritability values of the genes of F2 were relatively high and the environmental effect was relatively low.[Conclusion]The fruit length breeding of summer squash should be selected in early generation selection.

Analysis of Fruit Width Using Mixed Major Gene and Polygene Inheritance Model in Summer Squash

[Objective] The aim was to provide scientific basis for breeding on the fruit width of summer squash.[Method] Inheritance of the fruit width traits of summer squash in P1,P2,F1,BC1,BC2 and F2 from two crosses q-1×23-4G（cross 1）and q-1×A-7（cross 2）was investigated by the mixed major gene and polygene inheritance model of quantitative traits.[Result] The fruit width was controlled by B-1 model.Heritability values of the major genes of F2 were relatively high and the environmental effect was relatively low.[Conclusion] The fruit width breeding of summer squash should be selected in early generation selection.

Genetic Analysis of Cryotolerance in Cotton During the Overwintering Period Using Mixed Model of Major Gene and Polygene

The joint analysis of the mixed genetic model of major gene and polygene was conducted to study the inheritance of cryotolerance in cotton during the overwintering period.H077（G.hirsutum L.,weak cryotolerance） and H113（G.barbadence L.,strong cryotolerance） were used as parents.Cryotolerance of six generation populations including P1,P2,F1,B1,B2,and F2,from each of the two reciprocal crosses H077×H113 and H113×H077 were all investigated.The results showed that cryotolerance in cotton during the overwintering period was accorded with two additive major genes and additivedominance polygene genetic model.For cross H077×H113,the heritabilities of major genes in B1,B2,and F2 were 83.62,76.84,and 90.56%,respectively;and the heritability of polygene could only be detected in B2,which was 7.76%.For cross H113×H077,the heritabilities of major genes in B1,B2,and F2 were 67.42,68.95,and 83.40%,respectively;and the heritability of polygene was only detected in F2,which was 6.51%.In addition,the whole heritability in F2 was always higher than that in B1 and B2 in each cross.Therefore,for the cryotolerance breeding of perennial cotton,the method of single cross recombination or single backcross should be adopted to transfer major genes,and the selection in F2 would be more efficient than that in other generations.

Genetic Analysis of Embryo Production Frequency in Wheat × Maize Cross

A DH population derived from C49S-87/01Y1-1069 was used to study the inheritance of wheat haploid embryo production frequency（EPF） in wheat × maize cross with the mixed major gene and polygene inheritance model of quantitative traits. The results showed that the EPF of wheat × maize cross was controlled by two dominant epistatic genes and polygene with gene effects of 1.95 for the first major gene, 6.69 for the second one and 2.80 for the polygene. The inheritability of major genes was as high as 72.09%, suggesting that the differences in EPF among wheat materials were mainly influenced by genotype. However, non-genetic factors were still important, especially for wheat materials with low EPF.

Segregation Analysis on Genetic System of Quantitative Traits in Plants

Based on the traditional polygene inheritance model of quantitative traits,the author suggests the major gene and polygene mixed inheritance model.The model was considered as a general one,while the pure major gene and pure polygene inheritance model was a specific case of the general model.Based on the proposed theory,the author established the segregation analysis procedure to study the genetic system of quantitative traits of plants.At present,this procedure can be used to evaluate the genetic effect of individual major genes(up to two to three major genes),the collective genetic effect of polygene,and their heritability value.This paper introduces how to establish the procedure,its main achievements,and its applications.An example is given to illustrate the steps,methods,and effectiveness of the procedure.