No abstract

No abstract

No abstract

No abstract

A novel procedure was used to test for single locus heterosis in a substantially isogenic background in corn, (Zea mays L.). It was determined that the rd gene and its rdPw allele do not contribute to single locus heterosis for plant height. To explain why C30 induces heterosis in F1 hybrids, while ‘Pee Wee’ is relatively impotent, a hypothesis is proposed to the effect that C30 evolved from P39 by the addition of a mutagenic and heterotic duplicated chromosomal segment when Rd mutated to rd. In turn, ‘Pee Wee’ developed with the loss of the segment at the time rd mutated to rdPw.

No abstract

Two degenerative sweet corn mutants, C30, a mutant of P39, ‘Pee Wee’ a mutant of C30 and P39 were crossed with sweet corn inbred C15 to determine their relative abilities to promote heterosis in hybrids. Of the 3 inbreds, C30 had the greatest ability to promote heterosis when in combination with C l5; ‘Pee Wee’ was least effective. Evidently, not all degenerative mutants are capable of promoting marked heterotic effects.

Two degenerative sweet corn mutants, C30, a mutant of P39, ‘Pee Wee’ a mutant of C30 and P39 were crossed with each other and with 4 unrelated inbreds to ascertain their relative abilities to promote heterosis in hybrids. In these tests C30 often exceeded P39 in the promotion of hybrid vigor but ‘Pee Wee’ was relatively inefficient in stimulating heterotic effects.