The Evaluation of Common Bean (Phaseolus vulgaris L.) Genotypes under Water Stress Based on Physiological and Agronomic Parameters.

Drought affects common bean productivity, and the severity of its impact is expected to increase due to climate change. The use of versatile genotypes could contribute to securing future bean production. This study investigates the adaptability of 10 common bean genotypes of indeterminate growth type under water scarcity conditions by measuring agronomic and physiological parameters. The evaluation occurs under irrigation treatments applied at two different phenological stages (anthesis (WDA) and seed filling initiation (WDSF)). The recorded adaptabilities of the genotypes (G) showed that G10 produced the highest overall seed yield in the normal irrigation (NI) (197.22 g plant-1) and WDA (192.78 g plant-1), while the G6 had the highest yield at WDSF (196.71 g plant-1). For the genotype's average mean, chlorophyll content decreased by 10.5% under drought at WDSF. Net photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (E) were reduced at WDA by 53%, 80.8%, and 61.4% and at WDSF by 43.75%, 57.7%, and 36%, respectively, while relative water content (RWC) reduced by 16.48%, on average, for both stages. G10 and G6 showed adaptability when water scarcity occurred at an early (WDA) or later stage (WDSF), respectively, providing insights into using germplasm resources to cope with the drought effect.

Seed Yield, Crude Protein and Mineral Nutrients of Lentil Genotypes Evaluated across Diverse Environments under Organic and Conventional Farming.

Lentil is an important legume crop for human and animal dietary needs due to its high nutritional value. The effect of genotype and growing environment was studied on seed yield (SY), crude protein (CP) and mineral nutrients (macro and micronutrients) of five lentil genotypes grown at four diverse locations for two consecutive years under organic and conventional farming. The location within each year was considered as a separate environment (E). Data were subjected to over environment two-way analysis of variance, while a genotype (G) plus genotype × environment (GGE) biplot analysis was performed. Our results indicated the E as the main source of variation (62.3-99.8%) for SY, CP and macronutrients for both farming systems, while for micronutrients it was either the E or the G × E interaction. Different environments were identified as ideal for the parameters studied: E6 (Larissa/Central Greece/2020) produced the higher CP values (organic: 32.0%, conventional: 27.5%) and showed the highest discriminating ability that was attributed to the lowest precipitation during the crucial period of pod filling. E7 (Thessaloniki/Central Macedonia/2020) and E8 (Orestiada/Thrace/2020) had fertile soils and ample soil moisture and were the most discriminating for high micronutrient content under both farming systems. Location Orestiada showed the highest SY for both organic (1.87-2.28 t ha-1) and conventional farming (1.56-2.89 t ha-1) regardless the year of cultivation and is proposed as an ideal location for lentil cultivation or for breeding for high SY. Genotypes explained a low percentage of the total variability; however, two promising genotypes were identified. Cultivar "Samos" demonstrated a wide adaptation capacity exhibiting stable and high SY under both organic and conventional farming, while the red lentil population "03-24L" showed very high level of seed CP, Fe and Mn contents regardless E or farming system. This genetic material could be further exploited as parental material aiming to develop lentil varieties that could be utilized as "functional" food or consist of a significant feed ingredient.

Cold acclimation and low temperature resistance in cotton: Gossypium hirsutum phospholipase Dalpha isoforms are differentially regulated by temperature and light.

Phospholipase Dalpha (PLDalpha) was isolated from cultivated cotton (Gossypium hirsutum) and characterized. Two PLDalpha genes were identified in the allotetraploid genome of G. hirsutum, derived from its diploid progenitors, G. raimondii and G. arboreum. The genes contained three exons and two introns. The translated products shared a 98.6% homology and were designated as GrPLDalpha and GaPLDalpha. Their ORFs encoded a polypeptide of 807 amino acids with a predicted molecular mass of 91.6 kDa sharing an 81-82% homology with PLDalpha1 and PLDalpha2 from A. thaliana. A possible alternative splicing event was detected at the 5' untranslated region which, however, did not result in alternative ORFs. Cold stress (10 degrees C or less) resulted in gene induction which was suppressed below control levels (25 degrees C or 22 degrees C growth temperature) when plants were acclimated at 17 degrees C before applying the cold treatment. Differences in the expression levels of the isoforms were recorded under cold acclimation, and cold stress temperatures. Expression was light regulated under growth, acclimation, and cold stress temperatures. Characterization of the products of lipid hydrolysis by the endogenous PLDalpha indicated alterations in lipid species and a variation in levels of the signalling molecule phosphatidic acid (PA) following acclimation or cold stress.

Low temperature and light regulate delta 12 fatty acid desaturases (FAD2) at a transcriptional level in cotton (Gossypium hirsutum).

Lipid modifying enzymes play a key role in the development of cold stress tolerance in cold-resistant plants such as cereals. However, little is known about the role of the endogenous enzymes in cold-sensitive species such as cotton. Delta 12 fatty acid desaturases (FAD2), known to participate in adaptation to low temperatures through acyl chain modifications were used in gene expression studies in order to identify parameters of plant response to low temperatures. The induction of microsomal delta 12 fatty acid desaturases at an mRNA level under cold stress in plants is shown here for first time. Quantitative PCR showed that though both delta 12 omega 6 fatty acid desaturase genes FAD2-3 and FAD2-4 identified in cotton are induced under cold stress, FAD2-4 induction is significantly higher than FAD2-3. The induction of both isoforms was light regulated, in contrast a third isoform FAD2-2 was not affected by cold or light. Stress tolerance and light regulatory elements were identified in the predicted promoters of both FAD2-3 and FAD2-4 genes. Di-unsaturated fatty acid species rapidly increased in the microsomal fraction isolated from cotton leaves, following cold stress. Expression analysis patterns were correlated with the observed increase in both total and microsomal fatty acid unsaturation levels suggesting the direct role of the FAD2 genes in membrane adaptation to cold stress.

Addressing huge spatial heterogeneity induced by virus infections in lentil breeding trials.

BACKGROUND: Spatial heterogeneity can have serious effects on the precision of field experimentation in plant breeding. In the present study the capacity of the honeycomb design (HD) to sample huge spatial heterogeneity was appraised. For this purpose, four trials were conducted each comprising a lentil landrace being screened for response to viruses. RESULTS: Huge spatial heterogeneity was reflected by the abnormally high values for coefficient of variation (CV) of single-plant yields, ranging 123-162 %. At a given field area, increasing the number of simulated entries was followed by declined effectiveness of the method, on account of the larger circular block implying greater intra-block heterogeneity; a hyperbolic increasing pattern of the top to bottom entry mean gap (TBG) indicated that a number of more than 100 replicates (number of plants per entry) is the crucial threshold to avoid significant deterioration of the sampling degree. Nevertheless, the honeycomb model kept dealing with variation better than the randomized complete block (RCB) pattern, thanks to the circular shape and standardized type of block that ensure the less possible extra heterogeneity with expanding the area of the block. CONCLUSIONS: Owing to the even and systematic entry allocation, breeders do not need to be concerned with the extra spatial heterogeneity that might induce the extra surface needed to expand the size of the block when many entries are considered. Instead, they could improve accuracy of comparisons with increasing the number of replicates (circular blocks) despite the concomitant greater overall spatial heterogeneity.