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High temperature stress during reproductive stages of wheat is a leading constraint in achieving food security. The objectives of study were to investigate heat sensitivity of terminal stages of wheat, to optimize foliar selenium dose, to boost nonenzymatic antioxidants and to determine correlation of these nonenzymatic antioxidants with yield and quality attributes of wheat crop. The field experiment was conducted for two consecutive years at agronomic research area, University of Agriculture Faisalabad, Pakistan. It was laid out in a randomized complete block design under split arrangement, and treatments were replicated thrice. Main plot factor comprised of heat imposition treatments; H0 = Control; H1 = Heat from spike to grain filling; H2 = Heat from flowering to grain filling while in subplots doses of foliar selenium were maintained; Se0 = Control (water spray); Se25 = 25 mg L−1; Se50 = 50 mg L−1; Se75 = 75 mg L−1 and Se100 = 100 mg L−1. Impact of H1 was more damaging compared to H2 and H0 for all response variables. Higher levels of proline, phenolics and leaf selenium were recorded with foliar spray of selenium either at 75 or at 100 mg L−1 under H0, whereas under H1 and H2, significantly higher responses were observed with 100 mg L−1 selenium for these traits. Increases in leaf chlorophyll and grain protein contents were statistically alike with 75 and 100 mg L−1 selenium; while in case of 1000-grain weight, harvest index and grain yield three levels of foliar selenium (50, 75 and 100 mg L−1) performed equally well under all the three heat stress treatments. Moreover, strong positive and significant associations of proline, phenolics, leaf selenium and chlorophyll were measured with yield of wheat. Conclusively, more harmful impacts were recorded under H1 compared to H2 and H0; while 75 mg L−1 Se proved more beneficial under H0 and 100 mg L−1 Se under H1 and H2. Strong associations of biochemical and agronomic traits were observed. [ABSTRACT FROM AUTHOR]

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Six advance lines IR1, IR2, IR3, RF1, RF2 and RF3 and four cultivars Pirsabak-08 (PS08), Janbaz (JZ), Zam-04 (ZM04) and Kohat-10 (KT10) were crossed in line × testers fashion in spring 2011 to produce F1 hybrids. The experimental material consisting of 34 genotypes (10 parents and 24 F1 hybrids) were evaluated under irrigated conditions in triplicated randomized complete block design at Cereal Crops Research Institute (CCRI), Pirsabak, Nowshera, Pakistan during 2011-12. Data were recorded on tillers plant-1, spike length, grains spike-1, 1000-grain weight, biological and grain yield plant-1. Mean of 24 F1 hybrids was greater than mean of 10 parents for all traits studied. Among lines RF3 and testers ZM-04 were good general combiners for most of the yield traits including grain yield plant-1. Cross combination RF3 × PS08 proved as good specific combiner showing positive SCA effects for all traits including grain yield plant-1. Crosses viz. IR1 × JZ, RF2 × ZM04 and RF2 × KT10 proved as good specific combiners for all traits except 1000-grain weight. Another three set of crosses viz. IR2 × JZ, RF1 × KT10 and RF1× JZ proved as good specific combiners for all traits except grains spike-1, biological yield and grain yield plant-1, respectively. All aforementioned crosses expected to yield transgressive segregants with more grain yield compared to their parents as these cross combinations had positive SCA effects for grain yield plant-1. GCA to SCA variances ratio revealed predominantly non-additive gene effects in the inheritance of all traits in wheat. Development of high yielding varieties with improved traits is therefore suggested through selection in late segregating generations. [ABSTRACT FROM AUTHOR]

Soil temperature, herbicides and their application timings were studied to determine their effect on weed infestation in wheat during 2012-13. A randomized complete block design (RCBD) with split plot arrangement was used to layout the experiment where herbicide application timings viz; T1: 30 days after sowing (DAS) and 40 DAS (T2) were randomized in main plot whereas weedy check (W0), weed free (W1), Affinity 50 WP (carfentrazone + isoproturan) (W2) and Axial 0.50 EC (pinoxaden) + Buctril Super 60 EC (bromoxynil + MCPA) (W3) were kept in sub-plots, respectively. Results showed that herbicides reduced weed density and its dry weight considerably in contrast to weedy check. Moreover, Axial 0.50 EC (pinoxaden) + Buctril Super 60 EC (bromoxynil + MCPA) was found most effective regarding weed control. Overall, chemical weed control led to substantial reduction in weed infestation in wheat. However, yield and yield related attributes like fertile tillers m-2, spikelets per spike, grains per spike, 1000-grain weight, grain yield and harvest index were improved so far in weed control treatments as compared to weedy check whereas soil temperature pertaining to weed emergence rate was recorded as: 6-8 °C ? 8-10 °C ? 10-12°C. [ABSTRACT FROM AUTHOR]

Crop nutrient requirements vary in sole/mono and multiple cropping systems indicating the need for optimization of fertilization programs. This 2-years study was performed to investigate the influence of different strategies related to NPK fertilization timing viz. T1 (control, no NPK application), T2 (all PK at sowing, ½ N at tillering and ½ at booting), T3 (½ PK at sowing, ½ NPK at tillering and ½ N at booting), T4 (all PK at sowing, ½ N at sowing and ½ at tillering), T5 (all PK at tillering, ½ N at tillering and ½ at booting), T6 (all PK at tillering and N at booting) and T7 (all NPK at sowing) on growth, yield, agronomic nutrient use efficiency of nitrogen (NUEA) and economic benefits of relay-intercropped wheat in cotton. Fertilization timing significantly affected growth, yield and NUEA of wheat. Application of T4 (all PK at sowing, ½ N at sowing and ½ at tillering) caused maximum improvement in plant height, fertile tillers, grains per spike, biological yield, grain yield and NUEA. Economic analysis also manifested that the greatest net returns and benefit cost ratio (BCR) were obtained by same NPK application timing (i.e. T4). In conclusion, fertilization timing substantially affected the yield, NUEA and economic benefits of relay intercropped wheat in cotton; and application of ½ N and all PK at sowing and ½ N at tillering was most appropriate option. [ABSTRACT FROM AUTHOR]

Abstract: Boron (B) affects plant growth and development by influencing vital processes like cell division, cell wall formation, water relations, meristematic tissue growth, carbohydrate metabolism, and pollen tube growth which suggests plausible effects on all these activities due to its deficiency. Therefore, a field trial was set up to assess the efficacy of different levels (control, 0.01 M and 0.05 M) of foliar applied B at booting, anthesis, and grain filling growth stages of wheat crop respectively. Results revealed that B application at the rate of 0.05 M solution substantially increased plant height, productive tillers, 1000 grain-weight and final grain yield. It was observed that 0.05 M B applications at delayed growth stages after booting is less effective in improvement of yield attributes of wheat crop as compared to booting stage. Economic analysis revealed that 0.05 M B application gave highest net income and benefit-cost ratio. Thus foliar application of 0.05 M B application (foliar) at booting stage can improve wheat productivity possibly by optimizing post-vegetative plant metabolic activities during grain filling, in contrast to late application rate. [ABSTRACT FROM AUTHOR]