الفهرس 
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Abstract
Lentil (Lens culinaris Medik) cultivars suffering from several
constraints that limit and fluctuate production in Egypt. Three field trials were
conducted in this study at the Agricultural Experiment and Research Station,
Faculty of Agriculture, Giza, from 2006/2007 to 2008/2009 seasons. Each trial
was conducted as a split-split plot design in randomized complete blocks
arrangement with three replications. Main plots were assigned to two sowing
dates (beginning of November and 15th of November), sub-plots to three
planting seed rates (300, 450 and 600 seeds m–2) and sub–sub plots to five lentil
cultivars (Sinai 1, Giza 51, Giza 9, Giza 4 and Giza 370). Thus, this
investigation included 18 environments (2 sowing dates X 3 planting seed rates
X 3 seasons). The objectives were to elucidate the stability of studied lentil
cultivars under variable environmental conditions using four stability
parameters (coefficient of variance % (CV%), ecovalence (Wi), coefficient of
regression (bi ) and mean squares of deviation from regression (S2
d)), and
explore the interrelationships among yield and its components across
environments using path coefficient, and construct the suitable equation among
these relations through stepwise analysis. The heterogeneous data of studied
traits were transformed by arc sin, logarithm and square roots to avoid
misleading results. G x E interaction across 18 environments showed
significance for all studied traits, except for emerged plants percentage,
pods/plant and seed yield /plant. Therefore, the performance of cultivars varied
differently from one environment to another and stability analyses are valid for
traits that exhibited significant G x E.The calculated CV % of lentil cultivars for
the studied characters could classify characters into two groups: high and low
environmentally tolerant traits. However, a narrow range of CV values was
detected. Thus, this parameter is not very suitable for differentiating among
genotypes, particularly with transformed data. Ecovalence seemed to be the
most proper stability parameter for differentiating lentil genotypes rather than
Eberhat and Russell’s two parameters (bi and S2d).