Physical geography, isolation by distance and environmental variables shape genomic variation of wild barley (Hordeum vulgare L. ssp. spontaneum) in the Southern Levant

Determining the extent of genetic variation that reflects local adaptation in crop-wild relatives is of interest for the purpose of identifying useful genetic diversity for plant breeding. We investigated the association of genomic variation with geographical and environmental factors in wild barley (Hordeum vulgare L. ssp. spontaneum) populations of the Southern Levant using genotyping by sequencing (GBS) of 244 accessions in the Barley 1K+ collection. The inference of population structure resulted in four genetic clusters that corresponded to eco-geographical habitats and a significant association between lower gene flow rates and geographical barriers, e.g. the Judaean Mountains and the Sea of Galilee. Redundancy analysis (RDA) revealed that spatial autocorrelation explained 45% and environmental variables explained 15% of total genomic variation. Only 4.5% of genomic variation was solely attributed to environmental variation if the component confounded with spatial autocorrelation was excluded. A synthetic environmental variable combining latitude, solar radiation, and accumulated precipitation explained the highest proportion of genomic variation (3.9%). When conditioned on population structure, soil water capacity was the most important environmental variable explaining 1.18% of genomic variation. Genome scans with outlier analysis and genome-environment association studies were conducted to identify adaptation signatures. RDA and outlier methods jointly detected selection signatures in the pericentromeric regions, which have reduced recombination, of the chromosomes 3H, 4H, and 5H. However, selection signatures mostly disappeared after correction for population structure. In conclusion, adaptation to the highly diverse environments of the Southern Levant over short geographical ranges had a limited effect on the genomic diversity of wild barley. This highlighted the importance of nonselective forces in genetic differentiation.

Evaluation of blended fertilizer rates for improving production of food barley (Hordeum vulgare L.) in Semen Ari District, Southwestern Ethiopia

Depletion of soil fertility, depletion of macro- and micro-nutrients and soil organic matter and inappropriate and imbalanced fertilizer application are among the most important factors that reduces the food barley production in Ethiopia. Therefore, the experiment was conducted to evaluate NPSB blended fertilizer rate effect on improving production of food barley in Semen Ari District, Southwestern Ethiopia during main cropping season. Control, (142 NPS + 159 Urea) kg ha-1, (150 NPSB + 41 Urea) kg ha-1, (200 NPSB + 72 Urea) kg ha-1, (250 NPSB + 102 Urea) kg ha-1 and (100 NPSB + 161 Urea) kg ha-1 treatments were used for the experiment which laid out in RCBD following three replication with spacing of 20 cm between rows; and HB 1307 improved food barley seeds were drilled on prepared rows. Full dose of blended and potassium fertilizers were applied at planting time and urea was applied in two split. The result revealed that food barley responded well to application of N, P, S and B than the unfertilized one. Application of 100 kg ha-1 NPSB + 161 kg ha-1 Urea resulted in highest grain yield of 3806.3 kg ha-1, while the lowest grain yield of 1939.2 kg ha-1 was recorded from the nil. Moreover, the highest net benefit of 32124.56 ETB ha-1 and economic returns of 942.2% was recorded in response to application of 100 kg ha-1 NPSB + 161 kg ha-1 Urea. Application of 100 kg ha-1 NPSB + 161 kg ha-1 Urea gave 49.05% yield increment and 40.24% increment in economic return over the control. Therefore, we recommend application of 100 kg ha-1 NPSB + 161 kg ha-1 Urea for farmers and investor’s in study area and similar agro-ecologies as it was optimum for improving food barley production. Further studies and investigation should be done on plant nutrient uptake, nutrient use efficiency and over location. Int. J. Agril. Res. Innov. Tech. 11(2): 10-17, Dec 2021

Manipulation of Barley Development and Flowering Time by Exogenous Application of Plant Growth Regulators

Matching flowering time to the optimal flowering period in Mediterranean cropping zones is pivotal to maximize yield. Aside from variety selection and sowing date, growers have limited options to alter development in season. Plant hormones and growth regulators are used in perennial horticultural systems to manipulate development and floral initiation. In this study, a range of plant hormonal products were tested to analyze their effects on barley (Hordeum vulgare L) development by exogenous spray applications. Plants were grown in controlled conditions under long and short photoperiods with different vernalization treatments. The gibberellin (GA) products demonstrated the greatest potential for altering development. The GA inhibitor trinexapac-ethyl was able to delay the time to flowering in genetically divergent barley cultivars by up to 200 degree days under controlled conditions. A similar delay in flowering could be achieved via application at both early (GS13) and late (GS33) stages, with higher rates delaying flowering further. Notably, trinexapac-ethyl was able to extend the duration of pre-anthesis phases of development. By contrast, GA3 was unable to accelerate development under extreme short (8 h) or long (16 h) day lengths. There was also little evidence that GA3 could reproducibly accelerate development under intermediate 10–12 h day lengths. In addition, sprays of the cytokinin 6-benzyladenine (6-BA) were unable to reduce the vernalization requirement of the winter genotype Urambie. The present study provides baseline data for plant growth regulator treatments that delay cereal development. These treatments might be extended in field studies to align flowering of early sown crops to the optimal flowering period.

Plant growth promotion of barley (Hordeum vulgare L.) by potassium solubilizing bacteria with multifarious plant growth promoting attributes

Potassium (K) is the foremost macronutrients for growth of plant, soil health and fertility. The huge application of NPK chemical fertilizers negatively impacts the economy and is a threat to environmental sustainability. The rapid depletion of K mineral in soil is due to the application of agrochemicals agricultural fields for the production of crops in India. In present investigation, K-solubilizing microbes (KSM) were isolated and enumerated from cereal crops growing in Sirmour Himachal Pradesh. A total 125 bacteria were isolated and screened for K- solubilization on Aleksandrov agar plates and found that 31 bacterial strains exhibited K-solubilization. These 31 K-solubilizing strains of bacteria were additionally screened for other plant growth promoting (PGP) potential including solubilization of minerals, production of siderophores, ammonia, hydrogen cyanide and indole acetic acids. The performance of an efficient K-solubilizer was evaluated for plant growth promoting ability in pot assay under in vitro conditions. The strain EU-LWNA-25 positively influenced shoot length, fresh weight, carotenoids and total sugar content than the full dose, half dose and control. The strain enhancing physiological and growth parameters was identified by BLASTn analysis as Pseudomonas gessardii EU-LWNA-25. K-solubilizing plant growth promoting bacteria could be suitable bioinoculants for Rabi seasonal crops and overcomes the challenges of sustainable agriculture in K-deficient soil.