Genetics and Breeding of 42‐Chromosome Triticale. II. Relations Between Chromosomal Variability and Reproductive Characters1

Abstract

F2 plants from two hybrid populations of 42‐chromosome triticale (X Triticosecale Wittmack) in which one or more of the D‐genome chromosomes had been substituted for a corresponding number of rye chromosomes were analyzed for their meiotic stability (number of univalents at metaphase I). F2‐derived F3 lines were evaluated in field tests. Genetic variability was detected in both populations for grain yield and heading time, and in one of the two populations for spikelets/spike, pollen viability, and percentage fertility. Correlations with the number of rye chromosomes indicated that substitutions had no effect on meiotic stability or any of the agronomic characteristics analyzed. Correlations of the number of univalents with fertility and other characteristics were low, indicating that measurement of meiotic stability is apparently of little value as a selection criterion to improve either meiotic stability or fertility. The use of pollen viability would also be of limited value for selection for fertility or yield because the correlations were generally low and nonsignificant. However, differences between populations in amount of genetic variability for pollen viability indicated that this character might be useful in some populations though not in others.