Syed, Salim Shah (2006) RECURRENT SELECTION FROM MAYDIS LEAF BLIGHT RESISTANCE AND GRAIN YIELD IMPROVEMENT IN MAIZE. PhD thesis, NWFP Agriculture University, Peshawar.
Leaf blight of maize (Zea mays L.) caused by Bipolaris maydis (Nisik. And Miyake) is one of the major factors limiting maize production in the plain areas of Pakistan. Particularly in the North West Frontier Province (NWFP). The objectives of this study were to estimate heritability, selection differential, expected and observed response to selection for amydis leaf blight resistance grain yield maturity and plant and ear height and to determine progress from selection in two maize populations. Two cycles of S1 recurrent selection were conducted in broad based maize populations. Sarhad White (SW) and Azam. One hundred S1 lines of each population were compared with their respective original populations as checks. The experimental material was evaluated under artificial epiphytotics during 2003 and 2004 at NWFP Agriculture University Peshawar. Selection differentials, expected responses and heritability estimates were determined from the replicated S1 lines of the second cycle that were generated after random mating of selected S1 lines of the first cycle. Significant variations between the cycles were observed for all the traits except maturity. High heritability estimates. Desirable selection differentials and close correspondence of expected and observed response were manifested fro all the characters. Days to tasseling silking and pollen shedding decreased non-significantly in SW (3.01, 4.07 and 3.66% cycle-1) but approximately 1% cycle-1 increase was observed of maturity traits in Azam. Ear height and plant height were significantly increased in SW (20.97 and 17.52% cycle-1) while significantly decreased in Azam population by 6.87 and 3.23% cycle-1, respectively. Blight disease was significantly reduced from 2.9 to 2.3 in SW and from 3.1 to 2.5 in Azam population. One the other hand grain yield was significantly increased in SW from 2041 kg ha-1cycle-1 to 2528 kg ha-1 cycle-1 or 19.24% cycle whereas from 2346 kg ha-1 cycle to 2772 kg ha-1 cyucle-1 or 15.34% cycle-1 respectively. These findings suggested that S1 recurrent selections is effective in improving disease resistance and grain yield. However some additional cycles of selection may be necessary to further improved grain yield and resistance level to maydis leaf blight in these two maize populations.
|Item Type:||Thesis (PhD)|
|Uncontrolled Keywords:||Recurrent selection, selection response, selection differential, S1 lines, heritability, maydis leaf blight|
|Subjects:||Biological & Medical Sciences (c) > Biological Sciences(c1)|
|Deposited By:||Mr. Muhammad Asif|
|Deposited On:||24 Nov 2006|
|Last Modified:||04 Oct 2007 21:03|
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