MOLECULAR ASSESSMENT OF SOME RICE GENOTYPES
FOR LOW NITROGEN INPUT USE EFFICIENCY
Mohamed Ahmed Ahmed Abd El-Rahman
ABSTRACT
The present investigation was carried out at Genetics Department,
Faculty of Agriculture, Kafrelsheikh University, and Rice Research and
Training Center (RRTC), Sakha, Kafrelsheikh, Egypt.
Two experiments were conducted during 2007 and 2008 seasons,
respectively, in these experiments four nitrogen levels were applied (i.e. zero,
20, 40, 60 Kg N fed-1). The first experiment was conducted as a preliminary
evaluation of 105 genotypes. On the basis of the obtained results for yield and
its related parameters, 55 genotypes were selected to perform phenotypic and
molecular assessment in the second season. The studied traits were yield and
its components as well as nitrogen use efficiency and its components.
The selected genotypes were classified on the basis of grain yield into
efficient, inefficient, inferior and neutral categories. The partial factor
productivity and N productivity ratio were very good in differentiating the
efficient, inefficient, neutral and inferior genotypes.
RM223, RM246, RM242 and RM72 markers were used and revealed (a1
and a2), (b1, b2 and b3), (c1, c2 and c3) and (d1, d2, d3, d4 and d5) DNA
fragments, respectively. The fragments b2, b3, c3, and d3 showed superior
association with panicle length under different N-levels, while b2 and d3
fragments were superior in this regard with grain yield. On the other hand, d1
and c1 were superior with 1000 grain weight, but b2, b3 and d3 were superior
with nitrogen productivity ratio and b2, b3, d1 and d3 fragments were the only
fragments which expressed association with physiological nitrogen use
efficiency. Moreover, the fragment b3 was able to be expressed only in indica
genotypes.