Cultivated soils often are either deficient or possess toxic concentrations
of one or more mineral elements that adversely affect emergence,
growth, maturity, production potential, and/or nutritional quality
of common bean (Phaseolus vulgaris L.). Our objective was to
study the inheritance of resistance to soil Zn deficiency. The resistant
`Matterhorn' was crossed with the susceptible 'T-39'. The F1 was
backcrossed to Matterhorn (BC1) and T-39 (BC2), and advanced to
the F2. The two parents, F1, F2, BC1 , and BC2 were evaluated in a Zn
deficient field trial at Kimberly, Idaho in 2001. Plants were classified
as tall-healthy or stunted with chlorotic leaves. Leaves were sampled
from the two types of plants at flowering and analyzed for Zn concentration.
The tall plants had an average leaf Zn concentration of 22.5
mg kg- 1 . In contrast, stunted plants had a Zn concentration of 15.0
mg kg- 1. All F1 plants were tall resembling Matterhorn, except that
unlike Matterhorn (white flowers and seeds) they had purple flowers
and black shiny seeds. Thus, the resistance to Zn deficiency was
dominant. A segregation of 45 resistant (R) to 20 susceptible (S)
plants was observed in the F2, giving a good fit to 3 R:1 S (x2 = 1.1538,
P = 0.28). All plants in BC1 were resistant. In BC2, 142 It and 139 S
plants were observed, giving a ratio of 1 R to 1 S (x2 = 0.032, P = 0.86).
This supports a single dominant gene controlling soil Zn deficiency
resistance. The symbol Znd is proposed for the dominant allele controlling
resistance to soil Zn deficiency, and znd for its susceptible
counterpart
