Muhammad Ashfaq Wahid

Adoption of Bt Cotton: Threats and Challenges

Adopting new technology always involves advantages and risks; Bt cotton ( Gossypium hirsutum L.) is a new technology well known in developed countries for its many advantages, such as reduced pesticide application, better insect pest control, and higher lint yield. However, its success in developing countries is still a question mark. Global adoption of Bt cotton has risen dramatically from 0.76 million ha when introduced in 1996 to 7.85 million ha in the 2005 cotton-growing season where 54% of the cotton crops in the USA, 76% in China, and 80% in Australia were grown with single or multiple Bt genes. Bollworms are serious cotton pests causing 30-40% yield reduction in Pakistan and 20-66% potential crop losses in India. The major advances shown in this review include: (1) Evolution of Bt cotton may prove to be a green revolution to enhance cotton yield; (2) adoption of Bt cotton by farmers is increasing due to its beneficial environmental effects by reducing pesticide application: however, a high seed price has compelled farmers to use illegal non-approved Bt causing huge damage to crops because of low tolerance to insect pests; and (3) some factors responsible for changes in the efficiency of the Bt gene and Bt cotton yield include internal phenology (genetics), atmospheric changes (CO2 concentration), nutrition, insect pests, boll distribution pattern, disease and nematodes, removal of fruiting branch and/or floral bud, introduction of Bt gene, and terpenoids and tannin production in the plant body.

Removal of early fruit branches triggered regulations in senescence, boll attributes and yield of Bt cotton genotypes: Early fruit branch removal triggered regulations in Bt cotton genotypes

Premature senescence, unopened and rotted bolls are the primary constrictions hampering the accomplishment of yield potential in Bt cotton. An experiment was conducted with the objectives to delay senescence, enhance boll opening and reduce the boll rotting. The experiment was conducted at two randomly selected sites of University of Agriculture Faisalabad, Pakistan, during 2015 and repeated in 2016. Each experiment was laid out in randomised complete block design with two by two factorial arrangement structure and replicated five times. Treatments were comprised of R0 =no fruit removal; R1 = removal of early fruit branches (REFB) and two genotypes, viz. V1 =FH-142 and V2 =MNH-886. Genotypes were selected on the basis of abiotic stress tolerance (FH-142) and susceptibility (MNH-886). Nodes above cracked bolls, monopodial branches, opened bolls per plant and seed cotton yield were enhanced by 23, 12, 13 and 17%, respectively, under the influence of REFB over no fruit branch removal, while the REFB-mediated decrease in boll rotting was 27%. Moreover, the response of MNH-886 was more remarkable than FH-142 for all studied variables. Conclusively, REFB increased the number of nodes above a cracked boll, monopodial branches, opened bolls per plant and seed cotton yield while decreased rotted bolls per plant in both genotypes.

Influence of Soil Applied Boron on the Boll Retention, Productivity and Economic Returns of Different Cotton Genotypes

Cotton is major contributor in fiber and edible oil production of Pakistan. However, its growth and development is severely hampered by boron (B) deficiency in semi-arid regions of the country. This experiment was conducted to determine the influence of soil applied B (0.5, 1.0, 1.5, 2.0 and 2.5 kg B ha -1 ) on the performance of cotton genotypes FH-113, MNH-786 and CIM-496. Boron application significantly improved the boll retention, cotton seed yield, ginning out turn and net economic returns of cotton genotypes. In this regard, soil application at 1.5 kg B ha -1 was the most effective. Amongst the tested genotypes, FH-113 performed better than others. In conclusion, soil application of B at 1.5 kg ha -1 was the most cost effective in improving the yield and yield contributing traits of cotton and fetching the maximum net economic returns.

Management practices to control premature senescence in Bt cotton

ABSTRACT Commercial cultivation of Bt cotton produced higher boll load which led to stiff inter-original competition for photosynthates, resulting in early cessation of growth (premature senescence) due to more availability of sink and less sources. To overcome this problem, field experiment was conducted during 2011 and 2012 using five treatments of plant growth manipulation viz. no fruiting branch removal (F1), removal of first fruiting branch (F2), removal of first and second fruiting branch (F3), removal of all squares from first fruiting branch (F4), removal of all squares from first and second fruiting branches (F5), and three potassium (K) application rates viz. 50 kg ha−1 (K1), 100 kg ha−1 (K2), and 150 kg ha−1 (K3). More nodes above white flower were recorded in F5, followed by F3, while minimum were recorded in F1. Among potassium levels, maximum nodes above white flower were recorded in K3 followed by K2 and K1 during both years of study. Plant height recorded at physiological cutout stage or at maturity stage showed that plants gained more height with removal of all squares from first tosecond fruiting branches with higher potassium dose. Leaf K increased with increasing applied potassium and also with square/branch removal. So early removal of squares/fruiting branches along with higher potassium dose helped in delaying canopy senescence in Bt cotton.

Physiological response of late sown wheat to exogenous application of silicon

Late planting of wheat in rice-wheat cropping system is perhaps one of the major factors responsible for low crop yield. The main cause of reduction in yield is due to supra-optimal conditions during the reproductive growth. High temperature during reproductive phase induces changes in water relations, decreases photosynthetic rate, and transpiration rate, stomatal conductance and antioxidative defence system. Silicon (Si), being a beneficial nutrient not only provides significant benefits to plants growth and development but may also mitigate the adversities of high temperature. A field study was conducted at Agronomic Research Area of University of Agriculture; Faisalabad, Pakistan to assess the performance of late sown wheat with the soil applied Si. Experiment was comprised of three sowing dates; 10th Nov (normal), 10th Dec (late), 10th Jan (very late) with two wheat varieties (Sehar-2006 and Faisalabad-2008), and an optimized dose of Si (100 mg per kg soil), applied at different growth stages (control, crown root, booting and heading). Results indicated that 100 mg Si per kg soil at heading stage offset the negative impact of high temperature and induced heat tolerance in late sown wheat. Silicon application improved 34% relative water contents (RWC), 30% water potential, 26% osmotic potential, 23% turgor potential and 21% photosynthetic rate, and 32% transpiration rate and 20% stomatal conductance in wheat flag leaf than control treatment. Further it was observed that Si application preventing the oxidative membrane damage due to enhanced activity of antioxidant enzymes, i.e. 35% superoxide dismutase (SOD) and 38% catalase (CAT). In conclusion results of this field study demonstrated that soil applied Si (100 mg per kg soil) at heading stage enhanced all physiological attributes of wheat flag leaf. Which in turn ameliorated the adverse effects of high temperature in late sown wheat. Study depicted that Si can be used as a potential nutrient in order to mitigate the losses induced by high temperature stress.

Boron fertilization improves seed yield and harvest index of Camelina sativa L. by affecting source-sink

ABSTRACT The impact of soil (1, 2 kg ha−1) and foliar (100, 200 mg L−1) boron (B) with control (no B) was evaluated on phenology and yield formation of Camelina each applied at stem elongation and flowering stages. Foliar (200 mg L−1) or soil B (2 kg ha−1) resulted in earlier flowering and maturity, increased fruit bearing branches (19.68%), number of siliqua, seeds per siliqua (4.6%), biological yield (15%), seed yield (24%), harvest index (11.4%) and oil contents (23%) than no B. Increased fruit bearing branches, seed filled siliqua or seed numbers, harvest index and oil quality can be attributed to changes in dry matter accumulated of stem with simultaneous increase in siliqua dry weight with foliar or soil applied B. In crux, foliar (200 mg L−1) or soil applied (2 kg ha−1) B seems promising to improve seed and oil yield, harvest index of Camelina sativa under B deficient condition.

Influence of phosphorus application on growth, yield and oil quality of linola

ABSTRACT Influence of different phosphorus (P) sources on growth, yield and oil quality of linola was evaluated when randomized in complete block design using three replications. Treatments were control (No P), hydropriming, soil phosphorus (50 kg ha−1), seed inoculation with phosphate solubilizing bacteria (PSB, Bacillus spp.) and seed priming with single super phosphate (2%) alone and combined with reduced soil phosphorus (25 kg P ha−1). Among treatments, hydropriming and seed inoculation reduced seedling 50% and mean emergence time with highest emergence index, seedling fresh and dry weights and chlorophyll contents. Seed inoculation with soil P (25 kg ha−1) produced highest seeds per capsule, 100-seed weight, seed and biological yield, harvest index. Maximum oil percentage, low protein contents and high cost benefit ratio with net economic returns were also found for seed inoculation combined with soil phosphorus. Nonetheless, soil phosphorus application can be reduced when seed inoculation with PSB is employed.