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Phytochemicals with insect antifeedant potential can be used as a safer alternative to harmful chemicals that are used as grain protectants. The insect antifeedant effect of the extracts and fractions of Hemidesmus indicus root were tested against the stored grain insect pest Corcyra cephalonica Stainton. Bioactivity-guided study of ethanol extract of Hemidesmus indicus root led to isolation and identification of a triterpenoid, Lupeol with insect antifeedant potential. Although Lupeol showed insect antifeedant potential the ethanol extract was found to be more effective as an antifeedant. This implies that the synergistic action of compounds present in the ethanol extract of H. indicus root is responsible for the higher antifeedant potential.

Background: Barley (Hordeum vulgare L.) is one of the more important cultivated crops in the Mediterranean region, where drought and high temperatures during the grain filling stage are the main abiotic stresses limiting its production. The aim of this study is to evaluate the effects of the spike type on the grain yield, thousand kernels weight and some grain filling parameters.Methods: The present study was conducted on the experimental site of station ITGC in Setif, Algeria, eight Barley genotypes were tested during two cropping seasons (2017/2018 and 2018/2019) in a randomized block design with 3 replications.Result: The results proved significant effect of genotypes and spike types on the grain filling parameters, but no significant effect of spike type on the thousand kernels weight during the both cropping seasons. In addition, the spike type registered significant effect just during the second cropping season. Among the genotypes with 6 rows spike type the local genotype Fouarra have high grain yield (97.79 Q/ha) with a deviation of 37.57% from the total mean of the genotypes with 6 row spike type. Many studies proved that in 6-row barleys, the magnitude of contribution of grain number in grain yield was higher than contribution of grain weight. The grain growth of genotypes studied follows a sigmoid curve, during the first season (2017-2018) the duration of grain filling ranged between 24 days for Saida 183 and 28 days for Rihane 03, for the group of genotypes with 6 rows. In addition, the duration of grain filling for the 2 row genotypes varied from 24 days for G4 to 28 days for genotype G2. During the second season (2018-2019) and for the genotypes with 6 rows, the duration of the grain filling varied from 21 days for the Saida 183 and 26 days for the genotype Fouarra, for the genotypes with 2 rows the duration of grain filling ranged from 21 days for the genotype G2 to 26 days for the genotype G3. The correlation analysis between the grain filling parameters, GY and TKW demonstrate a significant and positive correlation between TKW and MGW and GFR (r = 0.82* and r = 0.84*, respectively). Overall, the genotype variation in grain filling velocity and duration was responsible for the difference in grain yield and the improvement in grain yield was achieved by the increasing in velocity or duration of grain filling.

Image analysis systems have been increasingly utilized for the assessment of plant growth and health for decades. We used in this study the software Mesurim Pro to evaluate the variation of the leaf reflectance at Red, Green and Blue and the variation of the senescence parameters. The analysis of variance revealed that the reflectance at different wavelengths (Red, Blue and Green) was highly significant genotypes effects (P < 0.001); for this parameter the good genotypes are those we have the lowest values such as G19. In addition, the preferable genotypes were those which have low values for the mean senescence and senescence velocity; based on this raison the best genotype was the introduce genotype G12. The genotypes effect was significant for the grain yield and thousand-kernel weight, for the chlorophyll content and the analysis of variance showed a significant effect of genotypes, the highest values registered by the introduced genotype G5 this one was in the same homogenize group of G2, G4, G8 and G18. The ranking of genotypes based on all parameters suggested that the genotypes G11, G12, G5, G15 and G18, respectively (introduce genotypes) were the ideal genotypes under these conditions.