Search

The experiment was carried out with 50 wheat lines to study their mean, range, cv (%), correlation co- efficient, and path co- efficient considering 14 different morphological characters at the experimental field of Regional Wheat Research Centre (RWRC), Bangladesh Agricultural Research Institute (BARI), Gazipur during December 2010 to April 2011. Significant variation was observed among the genotypes for all characters studied. In general, genotypic correlations were higher than the phenotypic correlations. It indicates that there was an inherent association among them which was adversely influenced by the environment. The correlation coefficients showed that, seed yield was negatively and significantly correlated with days to heading (DTH), plant height (PHT), days to anthesis (DTA), days to physiological maturity (DPM), and canopy temperature at anthesis stage (CTanth.) but only negatively correlated with canopy temperature at vegetative stage (CTveg.), canopy temperature at grain filling stage (CTgf.), spikelets per spike both genotypically and phenotypically and grain per spike showed genotypically negative correlation. Path analysis showed that plant height (PHT), days to physiological maturity (DPM), canopy temperature at grain filling stage (CTgf.), and thousand grain weight (TGW) influenced seed yield directly in positive direction but days to heading (DTH), days to anthesis (DTA), grain filling duration (GFD), grain filling rate (GFR), Chlorophyll content at anthesis stage (CHLA), canopy temperature at vegetative stage (CTveg.), canopy temperature at anthesis stage (CTanth.), spikelets per spike, and grains per spike had negative direct effect on seed yield. Considering analytical findings of correlation co-efficient, path co-efficient analysis and field performance, the genotypes G 3, G 10, G 11, G 12, G13, G 21, G 29, G 35, G 38, G 40, G 46 and G 48 were found suitable for future breeding programme.Bangladesh J. Agril. Res. 42(3): 571-588, September 2017

Genetic divergences of 50 wheat lines were studied through Mohalanobis’s D2 and principal component analysis for fourteen characters. Genotypes were grouped into four different clusters. Cluster II comprised maximum number of genotypes (twenty one) followed by cluster IV. The inter-cluster distance was maximum between clusters I and III (12.29) indicating wide genetic diversity between these two clusters followed by the distance between cluster I and cluster II (8.28), and cluster III and cluster IV (7.97). The minimum inter-cluster distance was observed between cluster II and cluster IV (4.193) followed by cluster I and cluster IV (4.339) and cluster II and cluster III(4.390) indicating that the genotypes of these clusters were genetically close. The intra cluster distance of all the four clusters was more or less low which indicated that the genotypes within the same cluster were closely related. The highest inter genotypic distance (0.9166) was observed between the genotypes G 40 and G 41and lowest (0.0993) between the genotypes G 22 and G 43. Among the characters, heading days, maturity days, plant height (cm), canopy temperature at vegetative stage, canopy temperature at grain filling stage, grain filling rate (g d-1m-2), 1000- grain weight (g), and grains spike-1 contributed most for divergence in the studied genotypes. Cluster I had the highest mean for grain yield (4711.2 kg/ha), grain filling rate (17.5 g d-1m-2), chlorophyll content at anthesis, and plant height (93 cm). Crosses between I & III, I & II, and III & IV have greater chances to generate more heterotic F1s. Considering magnitude of genetic distance, contribution of different traits toward the total divergence, magnitude of cluster means for different traits and performance the genotypes G10, G 11, G12, G35, G40, G48 of cluster I, G7 of cluster II, G41, G5,and G3 of cluster III and G46, G21 of cluster IV may be considered as good parents for future hybridization program to produce high yielding genotypes. DOI: http://dx.doi.org/10.3329/bjar.v39i2.20414 Bangladesh J. Agril. Res. 39(2): 189-196, June 2014

A field experiment was conducted at the central research farm of Bangladesh Agricultural Research Institute, Gazipur for two consecutive years to verify the yield response of wheat variety Prodip to different doses and split applications of N fertilizer to determine appropriate N dose and application method for increasing NUE and grain yield of wheat. The treatments comprised of 12 combinations of three doses of nitrogen (80, 100, and 120 kg/ha) from urea, which were assigned in the main plots and four methods of N splitting viz., application of all N as basal; 2/3rd basal plus 1/3rd as top dress at crown root initiation (CR1) stage; 1/2 basal plus 1/2 as top dress at CR1 stage; and 1/3rd basal with 1/3rd as top dress at CR1 plus 1/3rd as top dress at 1st node stage which were tested in the sub plots. Higher yield was achieved from N rate of 120 kgiha applied as three equal splits of one-third as basal during final land preparation, one-third as top dressing during CR1 and the rest one-third top dressing at first node stage. The yield advantage of wheat due to N treatments was attributed to higher thousand grain weight and spikes/m2. Nitrogen content in wheat grain and straw was not affected significantly by different N treatment and their combinations, whereas plant N uptake was significantly influenced by N rate and N splitting and also due to the interaction of N rate and N splitting. Total N uptake was maximum under N rate of 120 kg/ha applied as three equal splits as 1/3rd basal with 1/3rd as top dress at CR1 plus 1/3rd as top dress at 1st node stage. Split applications of sub-optimal dose of N (80 kg/ha) resulted in negative gain in apparent NUE, but split applications, especially three split applications (1/3rd basal, 1/3rd at CR1, and 1/3rd at 1st node stage) of higher dose of N (100 and 120 kg/ha) resulted in positive gain in apparent NUE. Keywords: Wheat grain yield; nitrogen management; N uptake and NUE DOI: http://dx.doi.org/10.3329/bjar.v36i2.9249 BJAR 2011; 36(2): 231-240