GENETIC-VARIATION IN THE RESPONSE OF PEA (PISUM-SATIVUM L) TO HIGH SOIL CONCENTRATIONS OF BORON

In a greenhouse experiment nine current Australian cultivars of pea were grown to flowering time under five levels of soil boron (0, 10, 20, 30 and 40 mg kg-1) applied to the soil. This study was conducted to identify the genetic range in tolerance to boron within the group and to identify specific responses which may be utilised as selection criteria in a breeding program. Significant differences in response to increasing levels of boron were found between cultivars for dry-weight yield, and boron concentrations were lowest in shoots of the most tolerant cultivars. Of the other parameters measured, emergence was not affected but plant height and the number of nodes were reduced and the severity of symptom expression increased at the higher boron treatments. Symptom expression was the most efficient observation for predicting the response of cultivars, as determined by dry-weight yield and concentration of boron in shoots, and it was found that the correlation coefficients between symptoms and the latter two measurements were r = -0.78 (p < 0.01) and r = 0.81 (p < 0.01), respectively. Early Dun, Dundale, Alma and Maitland were the more tolerant of the cultivars and these happen to be the most widely grown cultivars in southern Australia.