Genome-wide association study for spot blotch resistance in Afghan wheat germplasm

Spot blotch (SB), caused by Bipolaris sorokiniana, is a devastating disease of wheat globally, especially in South Asia and South America. Understanding the genetics of resistance to SB is important for developing breeding strategies to improve resistance. A panel of 301 genotypes from Afghanistan was phenotyped over two crop seasons using a mixture of virulent B. sorokiniana isolates and genotyped using DArTSeq to obtain genome-wide markers. Fifty genotypes (16.6%) showed disease scores less than the resistant control. Principal component analysis using the genotypic data clustered the genotypes into five different groups. Among models used for genome-wide association mapping, the multilocus mixed model, and fixed and random model circulating probability unification algorithms were most effective in identifying significant marker-trait associations (MTA). Twenty-five MTAs at p ≤ .001 were identified on chromosomes 1A, 1B, 1D, 2B, 2D, 3A, 3B, 4A, 5A, 5B, 6A, 7A, and 7D, indicating the quantitative nature of resistance to SB. Phenotypic variation explained by these markers ranged from 2.0% to 17.7%, and genomic regions on the chromosomes 1D, 2D, 3A, 3B, 4A, 5A, and 5B coincided with loci identified in previous studies. Three single nucleotide polymorphism (SNP) markers on chromosomes 1B (SNP 1113207) and 5A (SNPs 5411867 and 998276) were significant in both crop seasons as well as in the combined analysis across seasons. Marker 5411867 is close to Vrn-A1, shown to be associated with SB in previous studies. Furthermore, among known SB resistance genes, Sb2 on chromosome 5B was predicted to be significant in this panel.     

High frequency plantlet regeneration from nodal segment culture of female <Emphasis Type="Italic">Momordica dioica</Emphasis> (Roxb.)

An in vitro propagation method for female plants of Momordica dioica (Roxb.) has been established. The nodal segments were harvested and the cut ends of the explants were sealed with wax and then surface sterilized and cultured. Bud breaking occurred on Murashige and Skoog’s (MS) agar-gelled medium + 2.0 mg L⁻¹ 6-Benzylaminopurine (BAP) + 0.1 mg L⁻¹ Indole-3 acetic acid (IAA). The cultures were amplified by passages on MS medium supplemented with 1.0 mg L⁻¹ BAP + 0.1 mg L⁻¹ IAA. Further, shoot amplification (29.2 shoots per vessel) was achieved by subculturing of in vitro regenerated shoot clump on MS medium + 0.5 mg L⁻¹ BAP + 0.1 mg L⁻¹ IAA. The micropropagated shoots were subsequently transferred for root formation on half-strength MS medium + 2.0 mg L⁻¹ Indole-3 butyric acid (IBA) with 89% success rate. The in vitro-regenerated shoots were also rooted ex vitro with 34% success. These plantlets were hardened in the greenhouse and transferred to the field. The established protocol is suitable for true to type cloning of mature female plant of M. dioica.     

Tree biomass,resource use and crop productivity in agri-horti-silvicultural systems in the dry region of Rajasthan,India

A combination of silvicultural species [Prosopis cineraria (L.), Ailanthus excelsa Roxb. and Colophospermum mopane (J. Kirk ex Benth.)] were planted with horticultural species [Ziziphus mauritiana (L.), Cordia myxa (Forster), and Emblica officinalis (Gaertn)] and intercropped with wheat (Triticum aestivum). Z. mauritiana +P. cineraria combination produced greater fruit, fodder and fuel wood and was less competitive to wheat crop. Crop yield reduced by 5% to 23% in the agroforestry systems than the yield in sole crop plot. Lowest yield was in C. mopane + C. myxa combination. Fodder yield was 0.53, 0.20 and 0.07 t ha^?1 from C. mopane (cursive), P. cineraria and A. excelsa, respectively, whereas utilizable biomass was 2.63 t ha^?1 from C. myxa (cursive) + P. cineraria, 2.21 t ha^?1 from C. myxa (cursive) + C. mopane and 2.18 t ha^?1 from Z. mauritiana + P. cineraria combinations. Soil organic carbon and NH₄–N increased (by 7% and 8%, respectively), whereas NO₃–N and PO₄–P decreased in agroforestry compared to the sole tree plots. Primary root attributes of P. cineraria, A. excelsa and C. mopane were higher in agroforestry and mostly concentrated in the top 0–25 cm of the soil layer. Z. mauritiana + P. cineraria were the best combination with minimum yield reduction and were found to be beneficial in enhancing soil fertility.     

Impact of the use of biofertilizers on cotton ( Gossypium hirsutum ) crop under irrigated agro-ecosystem

High nitrogen fixing, phosphate solubilizing, phytohormones producing isolates of Azotobacter, Azospirillum, Acetobacter and Pseudomonas were used as inoculants for cotton. Important cultures were selected on the basis of their effect on root/shoot length and chemotactic behaviour. Selected bioinoculants were earlier tested for their beneficial properties like nitrogen fixation (ARA), ammonia excretion, IAA production etc. These bio-inoculants were further tested for phosphate solubilization property. Various chosen strains were tested with Desi (HD 123) and American (H 1098) cotton under field conditions (as for wheat). Plant height and boll weight were determined at the time of harvesting whereas survival rate of inoculated bacteria was determined after 30, 80 and 130 days respectively. In the year 2000–01, on the basis of boll number and boll weight plant^?1 AVK 51 (36; 76.2?g plant^?1), HT 57 (27; 56.9?g plant^?1), AC18 (33; 61.5?g plant^?1), Ala 27 (36; 61.4?g plant^?1) and Pseudomonas (34; 71.3?g plant^?1) were identified as significant both for American and desi cotton varieties. Highest survival rate was observed with Mac 68 (33.4 × 10⁵) followed by HT54 (31.5 × 10⁵) after 30 days of sowing, which decreased after 80 days and remained constant up to 130 days. This trend was observed with all the cultures. Similar results were observed in 2001–02. 25?kg ha^?1 N saving was observed with A. chroococcum (AVK51) bioinoculant for cotton crop.     

Effect of Diclofop and Linuron on Rye Grass (Lolium multiflorum), Control in Triticale (X Triticosecale), Wheat (Triticum aestivum), and Rye (Secale cereale)

Annual rye grass ( Lolium multiflorum Lam.) is a serious and wide spread problem in cereal crops. A field experiment with a promising herbicide diclofop [(±)-2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid] at 0.56, 0.84 and 1.12 kg ai/ha, in comparison to commonly used linuron [ N' -(3,4-dichlorophenyl)- N -methoxy- N -methylurea] at 0.84, 1.12 and 1.41 kg ai/ha was conducted to control rye grass ( Lolium multiflorum Lam.) in triticale (X Triticosecale Wittmack), wheat ( Triticum aestivum L.) and rye ( Secale cereale L.). The herbicides were applied as soil-incorporated, preemergence and post-emergence. Results showed that diclofop is less phytotoxic than Linuron and the postemergence application of these herbicides was more phytotoxic on all cereal crops. Diclofop applied at 1.12 kg/ha, gave almost 100 percent rye grass control and produced 45 and 115 kg/ha higher grain yields in pre- and postemergence methods, respectively, as compared to the soil-incorporated method.     

Protein digestability of vegetables and field peas (Pisum sativum)

Protein digestibility was found to be 60.4 to 66.5 percent in raw unprocessed seeds of different pea cultivars. Protein digestibility (in vitro) was improved by the common methods of domestic processing and cooking including soaking, dehulling, ordinary cooking, pressure cooking and sprouting of legume grains. Pressure cooking had more pronounced effect on protein digestibility followed by ordinary cooking, sprouting, soaking for 18 h and (12 h) and dehulling. Pressure cooking of soaked and dehulled seeds was noticed to give most improved protein digestibility.     

Assessment of nifH diversity in rhizobial isolates of different origin and the role of antioxidant in respiratory protection

Rhizobia diversity is considered as one of the most useful resources for bioprospecting due to their symbiotic nitrogen-fixing ability with members of Leguminosae. The highly conserved nature of the nitrogenase reductase gene (nifH) makes it an ideal molecular tool to determine the potential for biological nitrogen fixation in any environment. In the present investigation, 250 rhizobial strains were isolated from legumes belonging to different geographical locations of Chhattisgarh, India. Genetic diversity of the nitrogenfixing bacterial community was analyzed using the nifH gene-specific primer. The polymorphism was found among the nitrogen-fixing population of different sources and origin but not in same source of rhizobia. Further, the symbiotic plasmid DNA was characterized on the basis of size and copy number of plasmids. The plasmid number varying from one to three in different rhizobial isolates had a size greater than 23 kb, while in some rhizobial isolates plasmids were absent. In addition, to examine the role of ascorbate in respiratory protection, the clear black spot margin of ascorbate was observed in the endodermis region of the nodule whereas scarcely dispersed in the infected region. Therefore, our findings demonstrated that knowing the rhizobial nifH gene diversity along with copy number of the plasmid is important for strain identification, deciding its fertility, productivity standards, and potential of biological nitrogen fixation across the geographical region.     

The Influence of Johnsongrass Infestation and Nitrogen Rates on Grain Sorghum

Gram sorghum [ Sorghum bicolor (L.) Moench] is grown on marginal land and johnsongrass [Sorghum haiepense (L.) Pers] is the most common and hard to control weed in this crop. The agronomic performance of gram sorghum at different nitrogen (N) and johnsongrass infestation levels in the field has not been adequately investigated. Therefore, research was conducted on a Decatur silty clay loam soil (Rhodic Paleudult) to determine the influence of N rates (0, 40, 80 and 120 kg ha^-1) and johnsongrass infestation levels (0, 2, 4, 6 and 8 plants per 5 m crop row) on the growth and yield of grain sorghum (cv. GK522G) and johnsongrass. Increase in N rates increased seed weight, seed yield and percent protein in grain sorghum as well as dry matter and percent protein of johnsongrass. The increase in johnsongrass infestation (from 0 to 8 plants per 5 m crop row) significantly decreased the performance of grain sorghum and johnsongrass at all the N rates. The results suggest that 40 kg N ha^-1 with up to 2 johnsongrass plants per 5 m crop row or 80 kg N ha^-1 with up to 4 johnsongrass plants per 5 m crop row produced grain sorghum yields equivalent to absence of johnsongrass in the crop.     

Influence of split‐applied nitrogen on grain yield and protein content in ten grain sorghum culti‐vars 1

More information on the response of newly developed or introduced grain sorghum cultivare to split‐applied nitrogen (N) in semi‐arid rainfed agriculture is needed. Therefore, the influence of four split‐applied N schedules (100/0, 66/34, 50/50, and 34/66) on six American (SC 283, SC 274, SC 669, B 66181, SC 33, and RTam 428), and four West African (CSm 63, 1S 6704c, 1S 7173c, and 1S 7419c) grain sorghum cultivars was evaluated. The split‐applied N significantly increased grain yield and percent protein in grain sorghum over a one‐time application of N. The increase in yield and protein content varied among varieties and schedules of N application. Varieties SC 574, RTam 428, and Csm 63 at split‐applied schedules of 66/34, 50/50, and 34/66, respectively, gave the highest yield over one‐time application of N. Similar differences in percent protein in grain among cultivars due to split‐applied N were observed.     

Changes in phytates and HCl extractability of calcium,phosphorus, and iron of soaked,dehulled, cooked,and sprouted pigeon pea cultivar (UPAS-120)

UPAS-120, a high yielding and early maturing variety of pigeon peas releasedby the Department of Plant Breeding, CCS Haryana Agricultural University, Hisar contained a significant amount of phytic acid, i.e. 886 mg/100 g. When it was subjected to various domestic processing and cooking methods viz. soaking (6, 12, 18 h), dehulling, ordinary as well as pressure cooking and germination (24, 36 and 48 h), a drastic decrease in level of phytic acid with a remarkable increase in the HCl-extractability of mono, divalent, andtrivalent ions, like calcium, phosphorus, and iron occurred. Germination (48 h) was found to be the best method for decreasing the phytic acid content, i.e.35 to 39 percent less than the control and significantly (p<0.05) increasingthe non-phytate phosphorus and HCl-extractable phosphorus. Pressure cooking of soaked-dehulled pigeon pea also rendered equally good results. The calcium, phosphorus and iron contents of pigeon pea seeds were 197.3, 473.1, and 9.91 mg/100 g, respectively; some losses varying from 3 to 9 percent were noticed when the legume was subjected to soaking, cooking, and germination but the maximum losses, i.e. 23 percent, occurred when the seeds were dehulled. However, HCl-extractability of Ca, P and Fe improved to a significant extent when the pigeon pea seeds were soaked, soaked-dehulled, cooked and sprouted which may have been due to decrease in the phytate content followed by processing and cooking. The significant negative correlations between the phytic acid and HCl-extractability of minerals of processed pigeon pea strengthens these findings.