Yield and Phenological Responses of Bt Cotton to Different Sowing Dates in Semi-Arid Climate

Abstract

With the inclusion of BT cotton in the existing cotton-wheat cropping system of South Punjab, Pakistan; farmers are interested to sow early BT cotton to obtain its full production potential. There is a problem of sub and supra optimum temperature due to early and late sowing of BT cotton. Little efforts have been done to optimize the best sowing date of BT cotton in cotton-wheat cropping system. In this study, popular BT cotton cultivar MNH-886 was sown from February 14 till May 15, with two weeks interval, in soil filled earthen pots kept under natural conditions. Early sown (planted on February 14 and March 01) crop took more days to start emergence, complete 50% emergence and mean emergence time, and had minimum plant emergence. However, late sown (30 th April and 15 th May) took less time to germinate, with better and uniform seedling establishment. Although early planted crop took more days to start emergence, squaring, flowering, boll formation and boll opening but growing degree days to start emergence, squaring, flowering, boll formation and boll opening were high in late sown crop. However, BT cotton sown on 16 th March yielded better than all other sowing dates owing to increase in yield related traits like number of sympodial branches, bolls per plant and boll weight; while crop sown on 15 th May didn't perform well. Likewise sowing of BT cotton on 16 th March had better fiber quality in terms of ginning out turn, fiber length, strength, fineness and uniformity. There was a positive correlation of phenological events like days to start squaring, flowering, boll formation and boll opening with seed cotton and lint yield of BT cotton; and cotton yield and boll weight were also positively linked with fiber quality traits. In conclusion, planting of BT cotton on 16 th March is the best option to harvest higher seed cotton and lint yield of better quality fiber under arid to semi-arid conditions of South Punjab, Pakistan.

Maize yield, biomass and grain quality traits responses to delayed sowing date and genotypes in rain-fed condition

“…Gaile (2012) reported biomass of the whole maize plant was reduced by 7% to 12% when sowing was done 10 days later than the optimum planting date in Latvia under four years experiment. Similar results were also confirmed by Lawogbomo and Remison (2009) in maize and Shah et al, (2017) in cotton. However, the previous results were not always in consistent and the corn varieties specific variation is exist.…”

“…factor determining time of flowering and maturity in annual crops, including soybean, rapeseed and maize (Li et al, 2015;Shah et al, 2017). In present study, vegetative period (from emergence to silking) and total growth period duration also were both shortened, total period of the life cycle ranged from about 143 d in the normal sown treatment (DS0) to about 133d for DS10 and 127d for DS20 treatments for both species (Fig.…”

“…Increasing food demands by a growing human population require substantial increases in crop productivity in China and other developing counties (Liu et al, 2018). Sowing affecting maize growth and development (Shah et al, 2017;Shirzadi and Madani, 2008). In present study, crop growth and phenological events were significantly affected by delayed planting date.…”

Transplanting improves the allometry and fiber quality of Bt cotton in cotton–wheat cropping system

“…Transplanting of cotton seedlings may decrease the crop period without compromising its yield together with additional benefits like avoidance of thinning process and optimization of water use efficiency. Low temperature is one of the main challenges for cotton during the initial growing period so that germination decreases significantly (Shah et al, 2017a). Therefore, transplanting of BT cotton is a pragmatic solution under unfavorable circumstances.…”

“…Then, transplanting of cotton seedlings should avoid this limiting condition (Dong et al, 2007). However, wheat is harvested in late April while the optimum sowing time of Bt cotton is mid-March in Punjab, Pakistan (Shah et al, 2017a). This results in an overlapping period of 30-45 days and transplanting of 30-45 days old cotton seedlings may be an option to manage this overlapping.…”