EVALUATION OF MOLECULAR AND PHENOTYPIC DIVERSITY AND PHYSIOLOGICAL RESPONSES OF MELIA DUBIA TO MOISTURE STRESS
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Date
2019-10-25
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UNIVERSITY OF AGRICULTURAL SCIENCES, GKVK BENGALURU
Abstract
The present investigation was carried out to assess the genetic variability of Melia dubia
germplasm lines through molecular approach using SSR markers. From the results it is
found that forty-two accessions segregated into thirteen genetically distinct clusters,
indicating genetic diversity at molecular level. Further, growth of these lines was evaluated
for five years in the field which receives low rainfall of 660 mm annually. A wide variation
in growth was noticed among the forty-two lines under field conditions. To assess the
physiological reasons for variation in growth, a controlled experiment was conducted by
selecting ten accessions, of which five were the best and five were poor performing at field
level. These lines were vegetatively multiplied through softwood cuttings and grown at
field capacity and at 50% of field capacity (stress). From this study the Accessions MD058,
MD013 and MD111 recorded highest growth both under field capacity and at 50 %
moisture stress, while lowest growth was noticed in MD126 and 69 which corroborate with
their field performance. Germplasm lines that recorded highest growth has also recorded
highest photosynthetic rates both under field capacity as well as at 50 % moistures stress
and they also recorded higher WUE, better photosynthesis recovery rates after stress and
had higher drought susceptible index. The above results suggest that photosynthetic ability
of a plant is a primary driver of growth. From the above results accessions MD058, MD013
and MD111 were found to perform better under low rainfall conditions.