Assiut university researches
Genetic variation of morpho-physiological
traits associated with frost tolerance in faba
bean
Sallam, A., R. Martsch, Y. Moursi
Abstract:
Frost stress is one of the most significant abiotic stresses
affecting crops in Europe and limits e.g. winter faba bean
growth. Faba bean is therefore mainly sown as a spring crop
in cool-temperate regions. The objective of this study is to
study the genetic variation in frost tolerance between elite
winter faba beans. To address this challenge, 200 highly
homozygous lines were tested in a frost growth chamber.
Two different experiments, with frost stress and with
hardening conditions were conducted. A number of
morphological traits of shoots (loss of leaf turgidity, loss of
leaf color, regrowth after frost and disposition to survive) and
of roots (root frost susceptibility and root length) were visually
scored in the frost experiments. Moreover, total leaf fatty acid
(after hardening) and water content (after hardening and after
frost stress) in shoots as physiological parameters were
analyzed. The frost tolerance index was calculated to improve
two traits: disposition to survive and regrowth after frost. High
significant genetic variation was found between genotypes in
all traits scored and analyzed. Disposition to survive showed
high significant phenotypic (r = 0.77**) and genotypic (r =
0.85) correlations with regrowth after frost test. Moreover,
roots traits showed higher significant phenotypic and
genotypic correlations with frost tolerance than traits scored
on shoots (loss of leaf turgidity and loss of leaf color). For
physiological traits, water content before and after frost
showed stronger significant correlation with frost tolerance
than leaf fatty acid composition. Repeatability estimates (h2)
ranged from 0.58 to 0.95 for morphological traits and from
0.63 to 0.89 for physiological traits. The best 20 genotypes for
each morphological trait were determined. As a result, 12
genotypes were identified with superior frost tolerance. The
results indicate the possibility of genetically improving the
frost tolerance in winter faba bean through selection
programs.
Published in:
Euphytica ,In press,NULL