GrainGenes

II. 14. Comparison of yield and some yield components among strains with different genetic combinations of spring genes in barley.

S. Yasuda, The Ohara Institute for Agricultural Biology, Okayama University, Kurashiki, 710, Japan.

The purpose of this study is to compare the effects of different combinations of the spring genes on yield and yield components. The materials used amounted to 17 types of spring strains which had been made in the following way: two sets of isolines each differing only in a single spring gene, sh, Sh2^I, Sh2^II or Sh3 was produced by eleven backcrossings to both of an early and a late recurrent cultivars of winter type, Hayakiso 2 and Dairokkaku 1. Of these, Sh2^I and Sh2^II are the alleles exhibiting high (grade I) and moderate (grade II) spring growth habit. Then, these monogenic isolines with either Hayakiso or Dairokkaku backgrounds were crossed each other, and a total of desired 15 digenic strains were established after three selfed generations, although a genotype Sh2^ISh3 with Hayakiso's background was not obtained.

As seen in Table 1, the recessive spring gene sh seemed to exert little effect on yields and its components even in the presence of other spring genes, indicating that the sh was inert in the growth conditions at Kurashiki. The gene Sh3, regardless of genetic backgrounds, exerted strong influence on agronomic characters, and was epistatic to sh and also Sh2. Namely, the genotypes with Sh3 were 10 days or more earlier in heading time and less in ear number with elongated ear internodes and also ear length. As to grain yield per plant, the genotypes involving Sh3 with Hayakiso's background were evidently lower than those of the recurrent parent, Hayakiso 2. The effects of the genes Sh2^I and Sh2^II on agronomic characters are almost similar. Under the genetic background of Hayakiso 2, Sh2^I and Sh2^II retarded heading time for about 5 days, elongated stem length, shortened ear internodes, increased grain number per head and decreased harvest index, as compared with those of Hayakiso 2. However, the effects of both genes were not conspicuous in the genetic background of Dairokkaku 1.

Table 1. Means of recurrent parents shown in an actual number and percentages of the differences between spring strains and their recurrent parent to the recurrent parent.

The results of principal component analysis made by the use of correlation coefficients between the characters showed the spring strains scattered on the plane defined by the first (z1) and second (z2) principal component (Fig. 1) The first component, having its principal effects on stem length, ear number and grain yield, etc., seems to represent the amount of shoot growth. The second component, having principal effects on number of grains and ear length, etc., appears to be storage organs of the assimilates. As seen in Fig. 1, it is evident that the digenic and monogenic strains having Sh3 can be grouped, regardless of genetic backgrounds. Among spring strains not involving Sh3, two groups can be distinguished by their genetic backgrounds, though there are some exceptions. It may be considered that these groupings are due to the differences in heading time which have been affected by spring genes and also genetic backgrounds.

Fig 1. Twenty-three strains of monogenic and digenic spring types and their recurrent parents scattered according to the scores given by the first and second component vectors. (s:sh, 2:Sh2^I, 2':Sh2^II, 3:Sh3)

BGN 11 toc
BGN Main Index