http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Physiological, morphological, and biochemical criteria for the selection of potato germplasm that maintains yield under high temperatures
The potato suffers from yield reduction and loss of quality when grown at high temperatures. Determination of the relative contribution of total biomass and partitioning to yield stability, and documentation of morphological changes that occur in heat susceptible cultivars would be useful in selection of improved heat tolerant germplasm. Potato cultivars known to differ in yield under heat stress were studied in early and late season trials in two environmentally diverse Texas locations. Based on the cumulative degree days over a high temperature threshold, the environment was described as cool, warm, or hot. In the Lubbock warm environment, tuber yield was reduced, but biomass and its components were not, implying a higher temperature threshold for haulum compared to tuber growth. Total biomass was reduced in the two warmest environments, College Station warm and hot, but partitioning appeared to be the key element in yield stability. As night temperatures increased, plant morphology changed: relative area of new leaves decreased, leaf angles became more acute, the ratios of leaf to stem and tuber to root decreased, and root to biomass increased. The effect of warmer environments on both tuber yield and the major tuber protein, patatin, was studied. First, an improved method of purification of this protein was developed. Patatin antibody was used to quantify the relative amounts of patatin in tubers, roots, leaves and stems from three potato cultivars grown in three field environments that varied from relatively cool to hot. Generally, patatin levels increased in tubers as the environment became hotter. Material that cross-reacted with patatin antibody was found in leaf, stem and root tissue. However quantification of patatin in these tissues is uncertain since not all the isoforms in leaves, stems and roots have immunological identity with those in tubers. The appearance of patatin in leaf and stem tissue seemed to coincide with reduced tuberization and a warmer environment. It was proposed that patatin could be a useful biochemical marker in investigations of the effect of heat stress on potato tuber yield.