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Mung bean starch was subjected to continuous and repeated dry heat treatments at 130°C for 3–18 hr. Changes in structural, physicochemical, and digestive properties of mung bean starch during treatment were investigated. The starch retained a C‐type crystalline structure after continuous and repeated dry heat treatments. The dry heat treatments decreased the molecular weight, amylose content, swelling power, and viscosity of mung bean starch depending on treatment duration/cycles. Greater solubility and enthalpy values were found for the dry heated starch than those of the native ones. Additionally, the content of slowly digestible and resistant starch slightly increased during the early time/cycles of treatment. Furthermore, the dry‐heated mung bean starch showed a lower glycemic index than that of the native ones. And the continuous dry heat‐treated starch had the strongest changes in amylose content, solubility, swelling power, and pasting parameters compared to the repeated ones.

Excessive evaporative loss of water from the topsoil in arid-land agriculture is compensated via irrigation, which exploits massive freshwater resources. The cumulative effects of decades of unsustainable freshwater consumption in many arid regions are now threatening food-water security. While plastic mulches can reduce evaporation from the topsoil, their cost and non-biodegradability limit their utility. In response, we report on superhydrophobic sand (SHS), a bio-inspired enhancement of common sand with a nanoscale wax coating. When SHS was applied as a 5 mm-thick mulch over the soil, evaporation dramatically reduced and crop yields increased. Multi-year field trials of SHS application with tomato (Solanum Lycopersicum), barley (Hordeum vulgare), and wheat (Triticum aestivum) under normal irrigation enhanced yields by 17%-73%. Under brackish water irrigation (5500 ppm NaCl), SHS mulching produced 53%-208% higher fruit yield and grain gains for tomato and barley. Thus, SHS could benefit agriculture and city-greening in arid regions.

Background: Wheat stripe rust (caused by Puccinia striiformis f. sp. Tritici), is a major disease that causes huge yield damage. New pathogen races appeared in the last few years and caused a broke down in the resistant genotypes. In Egypt, some of the resistant genotypes began to be susceptible to stripe rust in recent years. This situation increases the need to produce new genotypes with durable resistance. Besides, looking for a new resistant source from the available wheat genotypes all over the world help in enhancing the breeding programs. Results: In the recent study, a set of 103-spring wheat genotypes from different fourteen countries were evaluated to their field resistant to stripe rust for two years. These genotypes included 17 Egyptian genotypes from the old and new cultivars. The 103-spring wheat genotypes were reported to be well adapted to the Egyptian environmental conditions. Out of the tested genotypes, eight genotypes from four different countries were found to be resistant in both years. Genotyping was carried out using genotyping-by-sequencing and a set of 26,703 SNPs were used in the genome-wide association study. Five SNP markers, located on chromosomes 2A and 4A, were found to be significantly associated with the resistance in both years. Three gene models associated with disease resistance and underlying these significant SNPs were identified. One immune Iranian genotype, with the highest number of different alleles from the most resistant Egyptian genotypes, was detected. Conclusion: the high variation among the tested genotypes in their resistance to the Egyptian stripe rust race confirming the possible improvement of stripe rust resistance in the Egyptian wheat genotypes. The identified five SNP markers are stable and could be used in marker-assisted selection after validation in different genetic backgrounds. Crossing between the immune Iranian genotype and the Egyptian genotypes will improve stripe rust resistance in Egypt.

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ABSTRACT Twenty-six genotypes of sunflower (16 F1-hybrids, four female lines, four restorer lines and two check varieties; Sakha 53 and Giza 102) were evaluated under two contrasting environments, i.e., loamy sand soil at A.R.C., Arab El-Awamer Res. Stn., and clay soil at Assiut Univ. Exper. Farm in season 2016. Genotypes mean squares of the studied traits was significant (P0.01) either in the separate or in the combined analysis. The differences between the two environments were significant for all traits except head diameter (HD). The genotype x environment interaction was significant for all traits, indicating differential responses of genotypes to the two environments. The sixteen hybrids showed negative significant heterosis (P0.01) for 50% flowering from the earlier check Giza 102 (standard heterosis; SH %), which ranged from -8.39 to -18.44% under loamy sand soil, and from -2.80 to -12.92% under clay soil. The heterotic effects were higher under loamy sand than under clay soil. The combined data showed that 4, 5 and 12 hybrids were significantly earlier than the mid-parent, better parent and the earlier check; respectively. The combined data over the two environments of plant height indicated that 15 hybrids showed negative significant standard heterosis ranged from -8.42 to -25.16%. This gives a good opportunity to select short sunflower hybrids. All the hybrids showed negative SH% for head diameter, and none of them exceeded the check variety in 100-SW. Otherwise, all the hybrids showed negative significant (P0.01) heterosis in husk% from the better check Sakha 53 either at the two environments or at the combined data. Over environments the SH% in oil% was positive and significant (p≤ 0.01) for four hybrids (ranged from 4.47 to 9.83%), for three hybrids in kernel weight and for one hybrid in number of seeds/head. Mid-parent heterosis in seed yield/head was positive and significant (P0.01) for 14 and 13 hybrids under loamy sand and clay soil; respectively, eight and three hybrids showed positive and significant BPH heterosis in seed yield/head under the respective environments. The positive and significant (P0.01) BPH in seed yield/head ranged from 16.54 to 685.33% under loamy sand soil, and from 13.42 to 70.38% under clay soil. Otherwise, only one hybrid No. 1 (A7 x Rf1) gave positive significant (P0.01) heterosis from the check hybrids Sakha 53 under clay soil and combined data. Mid-parent heterosis in oil yield/head was positive and significant (P0.01) for 14 hybrids under both environments and ranged from 3.35 to 823.12% under loamy sand, and from 3.01 to 151.88% under clay soil. Eight and three hybrids gave positive significant (P0.01) BPH under loamy sand and clay soil; respectively. The BPH in oil yield/head ranged from 9.48 to 708.95% and from 3.91 to 66.06% under the two respective environments. Standard heterosis in oil yield/head from the better check cultivar was positive and significant for five hybrids under loamy sand, one hybrid under clay soil and two hybrids in the combined data. Key words: Heterosis, Helianthus annuus L., Standard heterosis