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Ali F.,Pakistan Cereal Crops Research Institute | Ali F.,Huazhong Agricultural University | Zahid K.R.,Huazhong Agricultural University | Shah F.,Abdul Wali Khan University Mardan | And 7 more authors.
Australian Journal of Crop Science | Year: 2013

Flowering time is extremely crucial for reproduction and plays astonishing role in adaptation of maize to diverse environments. Several hundred S2 lines were developed in 2009 and 27 best S2 lines were crossed with three different testers in three isolations to generate testcrosses (Spring, 2010). The testcrosses were evaluated in a partial lattice square design with two replications to find out heterosis for maturity traits and develop early maturing hybrid (Summer, 2010). Significant correlation was observed among flowering time for both mid parent (MPH) and better parent heterosis (BPH). There were no significant correlation between different attributes for GCA and SCA revealing that heterosis and combining ability is trait dependent approach. The germplasm showed astonishing amount of phenotypic diversity and highly significant differences were observed except for kernel row number per ear. Negative MPH was observed among the testcrosses for flowering traits. WD 2 x 8 as a tester performed well than the other testers for ear length, while Jalal performed well for number of kernel row and 100-grain weight. Several lines among the total testcrosses showed negative values for GCA effect regarding flowering time and it can be concluded that these lines can be used as parental material for production of high quality inbred lines for different types of studies. The amount of variability observed for flowering traits and yield related characteristics could be used for production of high yielding early maturing hybrids. Furthermore, it can be concluded that early generation testing provides a promising tool for identification of germplasm at early stages and discards the poor combiners. © 2013. Source


Ullah H.,The University of Swabi Khyber | Subthain H.,Khyber Pakhtunkhwa Agricultural University | Khalil I.H.,Khyber Pakhtunkhwa Agricultural University | Khan W.U.,Khyber Pakhtunkhwa Agricultural University | And 2 more authors.
Pakistan Journal of Botany | Year: 2014

The climate is changing day by day and water scarcity has developed a milieu for the breeder to think accordingly. Twenty-four advanced wheat lines along with four prominent check cultivars were evaluated independently in irrigated (IRE) and rain-fed environments (RFE) for yield related traits at Khyber Pakhtunkhwa, Pakistan during 2010-11, using randomized complete block design with three replications under each test environment. Analysis of variance across the two environments exhibited highly significant variation (p≤0.01) among the genotypes for yield and associated traits. Differences among the two test environments (E) were significant for tillers m-2, 1000-grain weight and harvest index. Genotype × environment interaction (G×E) effects were significant only for 1000-grain weight and grain yield. There was general reduction in 1000-grain weight, biological yield and grain yield of all genotypes under RFE as compared to IRE. Magnitude of heritabilities estimates were greater for tillers m-2, spikelets spike-1 and grains spike-1 under IRE than RFE. Heritabilities were greater in RFE than IRE for spike length (0.31 vs 0.26), biological yield (0.80 vs 0.22), grain yield (0.94 vs 0.20) and harvest index (0.41 and 0.39). Relative high expected selection response was recorded for all characters under IRE except spike length, grains spike-1 and grain yield. In IRE, highest grain yield was produced by genotypes BRF-7 (5123 kg ha-1), B-VI(N)16 (5111 kg ha-1), B-IV(N)1 (5086 kg ha-1) and B-VI(N)5 (5049 kg ha-1), while genotypes B-VI(N)5 (4649 kg ha-1), B-IV(N)1 (4595 kg ha-1), BRF-7 (4486 kg ha-1) and B-IV(N)16 (4462 kg ha-1) were high yielding under RFE. Prominent stress selection indices used in the experiments were mean productivity (MP), tolerance (TOL), stress tolerance index (STI), trait index (TI) and trait stability index (TSI). MP and STI were the efficient and reliable selection indices in both environments (IRE & RFE). MP, TOL and STI had strong positive relationship with tillers m-2, spikelets spike-1, 1000- grain weight, biological yield and grain yield under IRE. Mean stress indices showed that the top ranking genotypes for MP and STI were B-VI(N)6, BRF-7, B-VI(N)5 and B-II(N)3, reflected their superior performance across both the conditions. Source

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