Citation
Almu, Hamisu
(2019)
Genotype-nitrogen-environment interaction and stability of blast resistant rice in multi locational trials.
Doctoral thesis, Universiti Putra Malaysia.
Abstract
Rice shortages have become a serious problem due to high demand as a result of
increasing world population. To meet the global rice demand by 2030, its production needs to be
increased by more than 50% worldwide. In Malaysia, the average rice production of 4.2 t/ha is
considered as low largely due to insufficient nutrients and blast disease. The main objective
of this study was to identify high yielding, blast resistant and highly stable rice genotypes
with high nitrogen efficiency for commercial cultivation in Malaysia. Sixteen blast-resistant rice
genotypes were evaluated in three rice granary areas (Tanjung Karang, Selangor; Kota Sarang
Semut, Kedah and Seberang Perai, Penang) with five different nitrogen fertilizer levels over two
planting seasons (Main and off seasons). Five nitrogen fertilizer levels:- 60, 80, 100,
120 (standard recommendation) and 140 kg N/ha were applied in each location and planting
season. The experimental design was a split plot design with three replications,
where the nitrogen fertilizer levels was assigned as main plot and rice genotypes as sub-plot.
Nitrogen levels had highly significant effects on all the yields and vegetative traits except,
panicle length, grain length and grain width. There was also presence of interaction between
genotype and nitrogen levels in all the environments on all traits except, number of
tillers per hill, number of panicles per hill and filled grain per panicle. In addition, the
genotype by nitrogen interaction was highly significant for all traits except unfilled grain
per panicle, panicle length, grain length, grain width and yield per hectare. The nitrogen
yield efficiency differed significantly with various levels of nitrogen applied. The optimum
nitrogen levels for MADA, Seberang Perai and Tanjung Karang were 112, 125 and 105 kg N/ha with
yield production of 9.53, 8.99 and 9.48 t/ha, respectively. The results revealed that the ideal
environment were ENV6 (Seberang Perai 2), ENV 2 (Tanjung Karang 1) and ENV4 (MADA 2). From the
result obtained on stability analyses, two genotypes (Genotype 9 and 16) were found to
be highly stable across the environments and produced high yield with 9.39 and 9.13 t/ha,
respectively. However, the agronomic nitrogen yield efficiency across environments for the two genotypes were 6.23% and
2.79%, respectively, at 140 kg N/ha. The two superior genotypes (Genotype 9 and 16) with high yield
and stability across environments are recommended for commercial
cultivation in Malaysia.
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