Submitted to: Plant Physiology
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2005
Publication Date: 7/1/2005
Citation: Hacisalihoglu, G., Vallejos, E., Kochian, L.V. 2005. Shoot-based mechanisms required for tolerance to soil zn deficiency in bean (phaseolus vulgaris l.). Plant Physiology. p. 75. Interpretive Summary:
Technical Abstract: An important area in micronutrient research involves the understanding of genetics of physiological responses of bean (Phaseolus vulgaris L.) to zinc (Zn) deficiency stress in soils, which is a major global agronomic problem causing considerable losses in bean productivity and quality. Further, genetic variability in bean would facilitate the improvement of Zn efficiency (ZE), which is the ability of plants to maintain high yield under low-Zn. We have used improved hydroponics and soil-based screening methods to assess the genetic diversity of 51 bean genotypes collected from different parts of the world. In the greenhouse study, plants were grown in low-Zn soil or Zn-supplemented soil (control) for 45 days. Bean genotypes differed significantly in their growth response, thus their ZE. Under Zn deficiency, the genotypes G4449, G11360, G12778, and G753 excelled all other lines in ZE. Zinc concentrations of old and young parts of the shoot did not show any relationship with ZE. Further, seed Zn content variability did not significantly affect the ZE of genotypes. Results of this study provided evidence for the highly diverse nature of bean genome for Zn efficiency. Using Zn-efficient and Zn-inefficient bean genotypes, we have shown that shoot-based mechanisms, especially biochemical utilization of Zn in leaves are associated with ZE. Finally, our segregation analysis with an F2 population derived from efficient and inefficient parents suggested that ZE was controlled by a single dominant gene. We are attempting to use this soil-based screening method together with hydroponics to search for molecular markers linked bean Zn efficiency. Data will be presented concerning our current model for physiological and genetic mechanisms controlling Zn efficiency.