Assuming a pedigree of parent-offspring mating, recombination effect on homozygosity by descent is studied numerically. Taking into consideration two linked loci, formulae for generalized inbreeding coefficient of parentage are shown. Under several initial conditions, resulting degrees of homozygosity by descent are calculated.
To establish all the possible types of primary simple trisomics of rice, spontaneous autotriploids were collected, pollinated with pollen of diploids, and their progenies were studied cytogenetically.
Variability of daughter root yield produced by directly planting sweetpotato was studied using typical strains belonging to direct-daughter type and indirect-daughter type, and the indirect-daughter type was considedered the most promising for direct planting because of its stable yield.
Self seed fertility in the artificially synthesized rape (C0-1) = colchi-amphidiploid = obtained from the crosses between n=10 and n=9 groups in Brassica, was extremely poor. In this paper, the author discrebes the change of self-fertility in the first to the fifth generation of CO-1. Seed-fertility describes the self-produced stocks of C0-1 was not high but generally low. However, when they were crossed with some commercial varieties of rape, their progenies showed as high fcrtility as the commercial varieties.
Fertilizer experiments of three rice varieties were made to estimate varietal differences in the responses to the three elements and in their interactions. Significant varietal differences were found not only for the effects on characters of individual fertilizers but also for their interactions. Differences between two years in certain interactions were also significant.
The relationship between morphological change and histochemical change of the shoot apex in Brassica with different ecotype varieties was studied. On the histochemical change, Periodic Acid Schiff, Protein, and Brachet reactions were examined. It was found that the ratio of three components stained with the above reactions was changed according to the morphological differentiation of the shoot apex.
Heritability estimates for individual selection which were obtained from variance components due to among and within half-sib families in sugar beets were compared with heritability values computed on the base of one cycle selection in a selection experiment. It was considered that in a small genotype×environment interaction a heritability estimate obtained from the analysis of variance in one location and year should have a considerably high confidence provided the variance components were adequately estimated.