Water relations composition among Egyptian cotton genotypes under water deficit

Background: water shortage is one of the major factor effects on growth characters and yield of most crops. Objective: this study was conducted to get to know the reactions of some Egyptian cotton genotypes to water deficit. Methods: The genetic materials used in this study included thirteen cotton genotypes belonging to Gossypium barbadense L., from the Cotton Research Institute (CRI), which was devoted to establishing the experimental materials for this investigation. Results: the ratio of GCA/SCA was less than unity for all studied indices, indicating predominance of non-additive gene action (dominance and epistasis), which is an important in exploitation of heterosis through hybrid breeding. Results: The data showed significant reduction in water relationship characters for all parental genotypes under stress conditions. The Egyptian variety Giza 68 gave high values for most water relationship characters. Data revealed that the greater the value of tolerance index is, the larger the yield reduction is under water deficit conditions and the higher the stress sensitivity is becoming. The parental genotypes Giza 96 showed the highest reduction in yield under water deficit conditions. At the same time, the cross combination Minufy x Australy showed higher values of yield reduction followed by the combinations Giza 67 x Australy. Of the male parents, the Russian genotype 10229 recorded the best GCA values for most water relationship characters. At the same time, the female parents, the old Egyptian genotype Giza 67 recorded the best values and exhibited good general combined for most water relationship characters. The cross combinations Giza 86 x Pima S6, Giza 77 x Pima S6, Giza 94 x Dandra and Giza 96 x Australy showed significant desirable SCA effect for most characters. Conclusion: relative water content %, osmotic pressure, chlorophyll and carotenoids content indicates better availability of water in the cell, which increases the photosynthetic rate. Also, the higher level of proline accumulation in the leaves which was recorded under deficit water suggests that the production of proline is probably a common response of plant under water deficit conditions.

Chlorfenapyr and Methomyl Deterioration on Spinach Plants and Their Residual Effects in Vitro on Egyptian cotton Leafworm (Spodoptera littoralis)

Field trials conducted to determine the degradation of chlorfenapyr and methomyl insecticides in/on spinach leaves. Spinach plants sprayed with chlorfenapyr (Challenger Super™ 24% SC) and methomyl (Neomyl™ 90% SP) at the rates of 50 cm3/100 L water and 715 g/ ha, respectively. The QuEChERS method used for the extraction and clean-up of the samples. Residue amounts determined at 2 h, 2, 4, 6, 9, 13 and 16 days after application by UHPLC-UV. The mean of recovery percentages was 98.78 and 99.05 % for chlorfenapyr and methomyl, respectively. The initial deposits of chlorfenapyr and methomyl on/in spinach leaves, two hours after a single application of the insecticides were 23.17 and 235.37 mg/kg, respectively. The percentages of dissipation of chlorfenapyr were 37.68, 55.29, 69.45, 84.45 and 96.83% for 2, 4, 6, 9 and 16 days after application. The corresponding dissipation percentages of methomyl were 38.27, 56.01, 71.44, 84.34 and 97.81%. The rates of degradation (k values) were 0.212 and 0.223, while the corresponding half-life times (t0.5) were 3.27 and 3.11 days with chlorfenapyr and methomyl, respectively. It could be recommended that single application of chlorfenapyr on Spinach plants at the early ages followed by single application of methomyl at least 17 days before harvest.

What You Eat Matters: Nutrient Inputs Alter the Metabolism and Neuropeptide Expression in Egyptian Cotton Leaf Worm, Spodoptera littoralis (Lepidoptera: Noctuidae)

Graphical AbstractThe parameters examined in Spodoptera littoralis larvae in response to four different diets, high-fat, high-sugar, calcium-rich and plant-based are shown starting with the developmental duration, weight, triglyceride and trehalose levels, lipid droplet structure, and finally with expression of four neuropeptide genes encoding adipokinetic hormone (AKH), insulin-like peptide 1 (ILP1), insulin-like peptide 2 (ILP2) and short neuropeptide F (sNPF).

Heritability and Genetic Advance as Genetic Indicators for Improvement in Two Cotton Crosses

The primary breeding goal for the Egyptian cotton breeding program is how to genetically improve both yield and fibre quality traits, while most of these agronomically traits are biometric traits. The objective of the present study is to evaluate variability and estimate frequency of transgressive segregants in order to isolate early superior individual plants which exceeding the better parent for some yield and fiber quality traits in two intraspecific cotton crosses in early transgressive segregating generation (F2 ). The F1 was highly significant superior than the better parent (Giza 97 and Giza 94) of the two crosses for all the studied traits except boll weight and lint %. Most of the studied traits in F2 generation showed high values of broad sense heritability coupled with low GAM % indicated that these traits controlled by non-additive gene action. All the studied traits had positive skewness sign except for lint %. Presley index and uniformity index for the two cotton crosses and upper half mean for cross II showed negative skewness. The negative skewness indicated that the population had more plants frequency with higher mean values than population mean and controlled by dominancy alleles. While, the traits that had positive skewness are controlled by additive gene action. The two cotton crosses showed transgressive segregants for all the studied traits. Cross I has higher transgressive index for yield traits than cross II, while cross II has the same trend for fiber quality traits than cross I. These results indicated that the both parents of the two cotton crosses had different alleles and genes governing the respective studied traits, which will help cotton breeder to combine beneficial alleles into a single genotype by rigorous selection process. This strategy could be used to improve many economic biometric traits by using better and stringent selection procedure to enhance Egyptian cotton productivity which is major concern in Egypt. The breeder can use transgressive segregation as an indicator of genetic variability to select the most superior plants.