Population dynamics of whitefly, Bemisia tabaci (Gennadius), as influenced by weather conditions infesting Bt cotton hybrid

To quantify the effect of different sowing environments and weather conditions on incidence of whitefly on cotton, experiments were conducted at PAU Regional Research Station, Bathinda during kharif 2014-2017) with Bt cotton hybrids 'NCS-855 BGII' at normal and late sowing. The mean incidence of whitefly was ranged from 0.0–39.5, 11.2–124.0, 0.2–26.4 and 0.7–15.5 adults/leaf during 2014, 2015, 2016 and 2017, respectively. The maximum adult population of whitefly was recorded in month of August almost in all the years, having its peak between 31–34 standard meteorological weeks (SMW). Among years, whitefly population was negatively correlated with rainfall, morning and evening relative humidity, while positively correlated with maximum temperature (except 2014) and minimum temperature (except 2014 and 2017). Moreover, bright sunshine showed positive correlation with whitefly population. In respect of pooled data, whitefly population showed negative correlation for minimum and maximum temperature and rainfall, while, positive correlation with morning and evening relative humidity and bright sunshine hours. Overall, crop sown at normal date was less affected by infestation of whitefly than late sown crop. So, this information would be helpful in developing efficient pest management strategies on cotton crop in order to get good harvest.

Microclimatic conditions and seed cotton yield as affected by sowing time, row orientation and plant spacing under Bt cotton hybrid

Microclimatic modifications are the effective and suitable adaptation strategy to minimize the adverse affect of weather on cotton. In this context, multi-location field experiments were laid out at Bathinda and Faridkot, districts of Punjab during Kharif 2018 with Bt-cotton hybrid RCH 773 BGII and sown at three times i.e., April 30, May 15 and May 30 with two row orientations (North-South: N-S and East-West : E-W) and three plant spacing’s (67.5 cm × 45.0 cm, 67.5 cm × 60.0 cm and 67.5 cm × 75.0 cm) in factorial split plot design and replicated by three times. The results revealed that during the morning (0730 IST) and afternoon time (1430 IST), soil and within-canopy temperature were found higher during emergence and mid growth stages with delayed sowing which reduced the crop growing period and resulted the seed cotton yield to be declined with delayed sowing. On the other hand, morning and afternoon within-canopy relative humidity was recorded higher with delayed sowing during sensitive stages of the crop which provided favorable weather for higher infestation of cotton insect-pest and disease and caused reduction in seed cotton yield at both the study locations. Soil temperature and within-canopy temperature were recorded higher in East-West row oriented, while within-canopy RH was higher under North-South row orientation at both the study regions. During entire growth period of cotton, soil temperature and within-canopy temperature recorded during morning and afternoon hours were found to be increased with increase in plant spacing whereas within-canopy relative humidity during morning and afternoon hours was found to be decreased with increase in plant spacing at both the locations. Among microclimatic parameters, higher variation was observed between sowing dates, while lesser variation was recorded among row orientations and plant spacings.

An enhanced photosynthesis and carbohydrate metabolic capability contributes to heterosis of the cotton (Gossypium hirsutum) hybrid ‘Huaza Mian H318’, as revealed by genome-wide gene expression analysis

Background Heterosis has been exploited for decades in different crops due to resulting in dramatic increases in yield, but relatively little molecular evidence on this topic was reported in cotton. Results The elite cotton hybrid variety ‘Huaza Mian H318’ (H318) and its parental lines were used to explore the source of its yield heterosis. A four-year investigation of yield-related traits showed that the boll number of H318 showed higher stability than that of its two parents, both in suitable and unsuitable climate years. In addition, the hybrid H318 grew faster and showed higher fresh and dry weights than its parental lines at the seedling stage. Transcriptome analysis of seedlings identified 17,308 differentially expressed genes (DEGs) between H318 and its parental lines, and 3490 extremely changed DEGs were screened out for later analysis. Most DEGs (3472/3490) were gathered between H318 and its paternal line (4–5), and only 64 DEGs were found between H318 and its maternal line (B0011), which implied that H318 displays more similar transcriptional patterns to its maternal parent at the seedling stage. GO and KEGG analyses showed that these DEGs were highly enriched in photosynthesis, lipid metabolic, carbohydrate metabolic and oxidation-reduction processes, and the expression level of these DEGs was significantly higher in H318 relative to its parental lines, which implied that photosynthesis, metabolism and stress resistances were enhanced in H318. Conclusion The enhanced photosynthesis, lipid and carbohydrate metabolic capabilities contribute to the heterosis of H318 at the seedling stage, and establishes a material foundation for subsequent higher boll-setting rates in complex field environments.

An enhanced photosynthesis and carbohydrate metabolic capability contributes to heterosis of the cotton (Gossypium hirsutum) hybrid ‘Huaza Mian H318’, as revealed by genome-wide gene expression analysis

Background: Heterosis has been exploited for decades in different crops due to resulting in dramatic increases in yield, but relatively little molecular evidence on this topic reported in cotton. Results: The elite cotton hybrid variety ‘Huaza Mian H318’ ( H318) and its parental lines were used to explore the source of its yield heterosis. A four-year investigation of yield-related traits showed that the boll number of H318 showed higher stability than that of its two parents, in both suitable and unsuitable climate years. In addition, the hybrid H318 grew faster and showed higher fresh and dry weights than its parental lines at the seedling stage. Transcriptome analysis of seedlings identified 17,308 differentially expressed genes (DEGs) between H318 and its parental lines, and 3,490 extremely changed DEGs were screened out for later analysis. Most DEGs (3,472/3,490) were gathered between H318 and its paternal line (4-5), and only 64 DEGs were found between H318 and its maternal line (B0011), which implied that H318 displays more similar transcriptional patterns to its maternal parent at the seedling stage. GO and KEGG analyses showed that these DEGs were highly enriched in photosynthesis, lipid metabolic, carbohydrate metabolic and oxidation-reduction processes, and the expression level of these DEGs was significantly higher in H318 relative to its parental lines, which implies that photosynthesis, metabolism and stress resistances were enhanced in H318. Conclusion: The enhanced photosynthesis, lipid and carbohydrate metabolic capabilities contribute to the heterosis of H318 at the seedling stage , and establishes a material foundation for subsequent higher boll-setting rates in complex field environments.

Enhanced photosynthesis and carbohydrate metabolic capability contributes to heterosis of cotton (Gossypium hirsutum) hybrid ‘Huaza Mian H318’ as revealed by genome-wide gene expression analysis

Background Heterosis has been exploited for decades in different crops for the dramatic increase in yield but less documented molecular evidences reported in cotton. Results An elite cotton hybrid variety ‘Huaza Mian H318’ (H318) and its parental lines was used to explore the source of its yield heterosis. A four years’ investigation of yield related traits showed that the boll number of the H318 was stable higher compare with its two parents whether in the climate suitable or unsuitable years. Besides, the hybrid H318 grows faster and showed higher fresh and dry weight than its parental lines at the seedling stage. Transcriptome analysis of seedlings identified 17,308 differential expressed genes (DEGs) between H318 and its parental lines, and 945 extremely changed DEGs were screened out for later analysis. In which, most DEGs (931/945) were gathered between H318 and its paternal line (4–5), but only 78 DEGs were found between H318 and its maternal line (B0011), which implied that H318 display more similar gene action with its maternal parent. GO and KEGG analysis showed that these DEGs highly enriched in photosynthesis and carbohydrate metabolic processes, the expression level of these DEGs was significantly higher in the H318 relative to its parental lines, which implies that sucrose and starch biosynthesis were enhanced in H318. Conclusion The enhanced photosynthesis and carbohydrate metabolic capability contributes to the heterosis of H318 at seedling stage, and establish the material foundation for later higher boll setting rates in the complex field environments.

Effect of Different Spacing of Bt and Non Bt Cotton Hybrid on Population of P. gossypiella under High Density Planting

A field experiment was conducted at Experimental farm of Department of Entomology, Dr. PDKV, Akola, on evaluation of various cotton cultivars against sucking pests under high density planting during kharif 2013 in Factorial Randomized Block Design with three replications. It is evaluated from the study that the higher population of P. gossypiella was harboured on Bt and non Bt cotton hybrid. The population of P. gossypiella larvae was in PKV Hy-2 and RCH-2 BGII was ranging from 0.25 to 1.28 and 0.05 to 0.11, respectively. The lowest mean population of P. gossypiella larvae (0.40) was observed in plant spacing of cotton 120 x 45 cm followed by plant spacing of 90 x 45 cm.