Describing the Genotypic Variation in Yield in Wheat to Cold Sensitive Response at High Altitude

Agriculture is one of the major sources of income and gainful employment for the people of
Uttarakhand state in India. Wheat based agriculture system contributes immensely to maintain
livelihood for a large section of people inhabited in hills of this state because of short growing season
in summer. Hill is considered as backward (i.e., not progressive) region since introduction of improved
varieties of seeds and transfer of advance agriculture technology cast little or no impact on promotion
and development of agriculture in this sector. Diversity in productive capacity of crop experience on
same site at different elevation of hill because constraints imposed by ecology did not permit such
movement to any unlimited extent. Low temperature becomes an important limitation for production of
grains in wheat cultivars as altitude increases. An alteration of growth habit accompanied with
changes in morphology of leaf, shoot and root characteristic and cool temperature induced sterility in
florets seemed to be associated with yield loss. In this investigation, as an initial approach possible
limits of some physiology related deterrent yield contributing traits are identified through study the
extent of variability of these characters, their relationship and relative contribution to grain yield
among 9 wheat cultivars (viz., HPW 155, HPW 236, HPW 277, HS 473, SKW 323, Sonalika, VL 829,
VL 832 and Local cultivar) grown under field condition at an elevation of 2100 m above mean sea
level (msl) at Ranichauri (78°24/N and 30°18/E). The results revealed an increase in average growing
degree days for head emergence and number of days experiencing lower soil temperature than air
temperature during anthesis together induced sterility in florets. An increase in thermal time at post
anthesis grain filling period encouraged the production of grains. Grain yield did not show significant
correlation with leaf, shoot and root characters. Susceptible cultivars, however, exhibited a greater
percentage of sterile florets in population, low grain yield, high root to shoot ratio, less thickness of
fresh leaves and less dry matter deposition. The varieties VL 829, HPW 236 and HS 473 showed
superior in yield and higher tolerance to cool conditions at high altitude.