Abstract
In non-traditional wheat production areas in Asia such as Bangladesh, Nepal and India, wheat sterility is a common problem, resulting in significant yield losses (Rerkasem, 1996a). Boron deficiency has been suggested as one of the factors contributing to wheat sterility- through its effects on. male (pollen) sterility (Rerkasem et al,, 1997). The critical stage of pollen development for B deficiency lies between the premeioticinterphase and the late tetrad/young microspore (Huang et al., 2000).
Unfavourable environmental factors may themselves cause male sterility, including water deficit (Saini and Aspinall, 1981 ), high temperature (Saini and Aspinall, 1982) and low temperature (chill/frost) (Huang et al., 1996). The concurrence of these factors may exacerbate effects of B deficiency on male sterility (Rawson, 1996).
In the present experiments, it was hypothesized that the effects of transient (temporary) B deficiency on male sterility may be exacerbated when wheat reproductive growth occurs in the late spring with high ambient temperature. High temperature is expected to increase leaf transpiration and decrease B transport into the ear, and therefore, exacerbate the response of male sterility to B deficiency during microsporogenesis.