GENETIC-STUDIES IN PEACH - INHERITANCE OF SWEET KERNEL AND MALE-STERILITY

Inheritance of the sweet kernel trait was studied in F-1 and F-2 famil ies generated by crossing 'Summer Beaut' nectarine (sweet kernel) with 'Ellerbe' and 'Biscoe' peach. F-1 plants showed bitter kernel. Segreg ation in the F-2 fit a 3 bitter : 1 sweet phenotypic ratio, suggesting that sweet kernel is controlled by a single recessive gene, for which the symbol sk is proposed. Sweet kernel (sk) was linked to nectarine (g) at a map distance of 12 cM. Seed bitterness phenotype is controlle d by the genotype of the maternal tree and not the genotype of the ind ividual embryo. Inheritance of male sterility derived from plant intro duction (PI)240928 and allelism of male sterile genes found in 'Chines e Cling' and 'White Glory' were investigated. Analysis of F-1, F-1 ope n-pollinated, and BC1 families derived from crossing PI240928-with six different wild-type cultivars showed that male sterility in PI240928 is controlled by cytoplasmic factors. Allelism studies showed that the male-sterile gene found in 'White Glory' is not allelic tops found in 'Chinese Cling', and hence is designated ps2.