Chromosomal variations for boron tolerance in wheat (Triticum aestivum)

Abstract

Monosomic plants of a moderately boron (B) tolerant wheat variety (Condor of homoeologous groups four and seven) were identified cytologically and then crossed as the female parent to six B tolerant wheat varieties; G 61450, Halberd, India 126, Benventuto Inca, Lin Calel and AUS 4041. Monosomic F_l hybrid plants of each cross were identified and used as both male and female parents in backcrosses to the Condor monosomic parental lines. Each pair of the 68 reciprocal families was then compared for the differences in response to B between the homologous chromosomes of the tester Condor monosomic lines and the tested varieties. The backcross reciprocal monosomic analysis indicated that there was chromosomal variation between the different varieties. The significant increase in root length resulting from the presence of chromosome 7B of Halberd and 4A of Benventuto Inca, G 61450 and India 126 were responsible for tolerance to B. The significant difference between the mean root length of the critical family for chromosome 4A from India 126 and that of the family for chromosome 4A from Condor was less than expected, indicating that there was probably another chromosome also responsible for tolerance to B in India 126.