Enhancement of germination and yield of cotton through optical seed priming: Lab. and diverse environment studies.

The current study demonstrates the practical application of optical seed priming technology to improve cotton seed germination, plant growth, crop yield, and fiber quality. The hypothesis of this study is that seed irradiation with different colors of light can improve germination and cotton productivity in different environments. In the priming of cotton seeds, a wider range of the light spectrum was used, ranging from ultraviolet (UV) to red wavelengths. Various light sources such as blue LED, red LED, diode laser, UV-B, and UV-C were studied, along with different exposure times and energy densities. The exposure time ranged from 1.0 to 36.0 minutes, while the energy density doses varied from 88 to 7550 mJ cm-2, depending on the light source. In laboratory conditions, the investigation on the impact of optical seed priming on germination showed a maximum improvement of up to 180% compared to the control group. Among the different light sources and energy densities, blue LED light was found to be the most effective for enhancing cotton seed germination across different varieties. To validate the findings from the laboratory, large-scale field trials were conducted in two different environments in Pakistan, namely Tandojam and Faisalabad. The field trials demonstrated significant improvements in germination and yield, with increases of up to 37% and 74% over the control group, respectively. Once again, blue LED light emerged as the best light source for optical seed priming at the farm level. These field trials provided encouraging results, indicating the potential of the eco-friendly optical seed priming technique. The study suggests that optical seed priming can be a commercially viable technology for improving cotton seed germination, plant growth, crop yield, and fiber quality. By utilizing this technique, growers and researchers in developing countries can address the challenge of poor cotton germination and potentially enhance their agricultural productivity.

Development and evaluation of triple gene transgenic cotton lines expressing three genes (Cry1Ac-Cry2Ab-EPSPS) for lepidopteran insect pests and herbicide tolerance.

Cotton is an international agricultural commodity and the main cash crop of Pakistan of which quality and quantity are subject to various whims of nature. Climate change, insect pest complex, and weeds are reducing its productivity. Here, we have developed triple gene cotton containing EPSPS gene along with two Bt toxin genes Cry1Ac and Cry2Ab using a strategy where all three genes are cloned in the same T-DNA, followed by successful cotton transformation via Agrobacterium-mediated transformation. This strategy has been developed to help cotton breeders in developing new cultivars by incorporating these genes into the non-transgenic or single Bt (Cry1Ac) gene cotton background where all three genes will inherit together. The expression of all three proteins was confirmed through immunostrips and was quantified through enzyme-linked immunosorbent assay (ELISA). The spatio-temporal expression of Bt protein in different parts of triple gene NIBGE cotton plants was determined. Maximum expression was found in leaves followed by seeds and boll rinds. Insect bioassays with cotton bollworms (Helicoverpa armigera), armyworms (Spodoptera litura), and pink bollworms (Pectinophora gossypiella) showed more than 90% mortality. The best performing line (NIBGE-E2) on the basis of spatiotemporal expression, glyphosate assays, and insect mortality data, was used for event characterization by using the genome sequencing approach. The event was successfully characterized and named NIBGE 20-01. A diagnostics test based on event-specific PCR was developed and its ability to distinguish NIBGE 20-01 event from other commercial transgenic cotton events was confirmed. To confirm stable expression of all three proteins in the field conditions, homozygous transgenic lines were grown in the field and the expression was confirmed through immunostrip assays. It was found that all three genes are expressed under field conditions. To show that all three genes are inherited together upon crossing with local elite cotton lines, the F1 generation was grown under glasshouse and field conditions. The expression of all three genes was confirmed under field conditions. Our results showed that transgenic cotton with three genes cloned in the same T-DNA can express all genes and can be conveniently transferred into elite cotton lines through a single cross.

Identification of Heat Tolerant Cotton Lines Showing Genetic Variation in Cell Membrane Thermostability, Stomata, and Trichome Size and Its Effect on Yield and Fiber Quality Traits.

Heat stress in cotton reduces its productivity. The development of heat-tolerant cotton varieties having resilience against changing climate is feasible. The purpose of this study was to probe the genetic variability in upland cotton for heat tolerance, the association of cell membrane thermostability (CMT), stomata, and trichome size with cotton adaptation to high temperature and effective breeding strategy to advance the valued traits. Relative cell injury percentage (RCI%) in studied genotypes ranged from 39 to 86%. Seventeen genotypes were found heat tolerant on the basis of low RCI%, heat susceptibility index (HSI<1), higher number of boll/plant, and seed cotton yield (SCY). Scanning electron microscopy (SEM) of heat-tolerant genotypes revealed the presence of different size of stomata (21.57 to 105.04 µm2) and trichomes (177 to 782.6 µm) on leaves of selected genotypes. The regression analysis showed a strong and negative association of RCI% and stomata size with SCY. However, no association was observed between the trichome size, yield, and fiber traits. On the overall location basis, a significant genotype × environment interaction was observed. All selected genotypes produced a higher SCY as compared with check varieties. But the stability analysis showed that the high yielding genotypes NIA-M-30, NIA-80, NIA-83, and CRIS-342 were also wide adaptive with unit regression (bi∼1) and non-significant deviation from the regression line (S2d∼0). The ability for the combination of some heat-tolerant genotypes was estimated by using the line × tester method among nine hybrids along with their 3 testers (i.e., male) and 3 lines (i.e., females). Genotypes, CRIS-342 and NIA-Perkh, were observed as best general combiners for SCY with a negative general combining ability effects for RCI%. Five hybrids showed a positive specific combining ability and heterotic effects for studied traits and also found lowest for HSI. RCI% and SCY/plant displayed higher estimates of heritability and genetic advance, indicating the heritability due to additive gene effects and chances of effective selection. The identified heat-tolerant and wide adaptive germplasm can be further advanced and utilized in cotton breeding programs for developing heat-tolerant cultivars. Selection criteria involving CMT and stomata size concluded to be an effective strategy for the screening of heat-tolerant cotton.