Studies on physiological and molecular diversity in wheat (Triticum aestivum L.) genotypes for phosphorus efficiency
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Date
2013
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CCSHAU
Abstract
Twelve wheat genotypes WH147, WH711, WH1021, WH1025, WH1080, WH1081, WH1094, WH1107, WH1111, C306, Lok-1 and PBW343 were evaluated at three P level; 100 %, 50% and 15 % P levels. All growth parameters such as plant height, dry weight, P content, grain growth rate, spike length, number of productive tillers and grain yield decreased at reduced P levels (50 % and 15 %). Total plant biomass was maximum in WH1080 and WH1111 at low P levels. P content in all plant parts decreased with decreasing P levels at all sampling stages. At later growth stages more of P accumulated in reproductive parts. Maximum spike and grain P content was observed in WH1080 and WH147. Minimum decrease in grain yield at 15 % P level was observed in WH147 (16.1 %), WH1080 (20.7 %) and WH1081 (26%). A significant positive correlation of grain yield was observed with total plant biomass (0.88), number of productive tillers (0.75), grain growth rate (0.74) and P content in grain (0.84). Also a delay in heading, anthesis and maturity was observed under P deficiency. C306, WH1081, Lok-1 and WH1080 had minimum delay in heading, anthesis and maturity.
Photosynthetic rate, chlorophyll content, transpiration rate and stomatal conductance decreased
with decreasing P levels. The genotypes which performed well at low P level were WH1080, WH1094,
WH1081 and WH147 and least efficient genotypes were C306 and PBW343. Phosphatase activity (acid
phosphatase, alkaline phosphatase and phytase) increased in response to P deficiency. WH1080, WH147 and WH1094 showed greater increase in enzyme activity under long term P deficiency. Genotypes WH1080,
WH147, WH1081and WH1094 performed well under short term P deficiency (15 days) in terms of root
traits (root length, number of secondary roots and root/shoot ratio). Lok-1 performed better in terms of
APase activity and WH1080, WH1025 and WH1094 performed well in terms of alkaline phosphatase and
phytase activity. Increased phosphatase activity and proton extrusion in root exudates was also observed
under P deficient conditions. Maximum enzyme activity in root exudates was found in WH1107 and
WH1080 and maximum exudation of protons was observed in WH1080. On the basis of RAPD - cluster
analysis two major groups were formed and these are further divided in four sub groups. The genotypes
which exhibited low diversity at phenotypic level also exhibited less genetic diversity at molecular level. On
the basis of present investigations WH147 and WH1080 were identified as more P efficient genotypes.
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Keywords
Planting, Vegetative propagation, Wheats, Developmental stages, Enzymes, Genotypes, Acidity, Yields, Grain, Inorganic acid salts