Increased yield stability of field-grown winter barley (Hordeum vulgare L.) varietal mixtures through ecological processes

Crop variety mixtures have the potential to increase yield stability in highly variable and unpredictable environments, yet knowledge of the specific mechanisms underlying enhanced yield stability has been limited. Ecological processes in genetically diverse crops were investigated by conducting field trials with winter barley varieties (Hordeum vulgare), grown as monocultures or as three-way mixtures in fungicide treated and untreated plots at three sites. Mixtures achieved yields comparable to the best performing monocultures whilst enhancing yield stability despite being subject to multiple predicted and unpredicted abiotic and biotic stresses including brown rust (Puccinia hordei) and lodging. There was compensation through competitive release because the most competitive variety overyielded in mixtures thereby compensating for less competitive varieties. Facilitation was also identified as an important ecological process within mixtures by reducing lodging. This study indicates that crop varietal mixtures have the capacity to stabilise productivity even when environmental conditions and stresses are not predicted in advance. Varietal mixtures provide a means of increasing crop genetic diversity without the need for extensive breeding efforts. They may confer enhanced resilience to environmental stresses and thus be a desirable component of future cropping systems for sustainable arable farming

APETALA2 control of barley internode elongation

Many plants dramatically elongate their stems during flowering, yet how this response is coordinated with the reproductive phase is unclear. We demonstrate that microRNA (miRNA) control of APETALA2 (AP2) is required for rapid, complete elongation of stem internodes in barley, especially of the final 'peduncle' internode directly underneath the inflorescence. Disrupted miR172 targeting of AP2 in the Zeo1.b barley mutant caused lower mitotic activity, delayed growth dynamics and premature lignification in the peduncle leading to fewer and shorter cells. Stage- and tissue-specific comparative transcriptomics between Zeo1.b and its parent cultivar showed reduced expression of proliferation-associated genes, ectopic expression of maturation-related genes and persistent, elevated expression of genes associated with jasmonate and stress responses. We further show that applying methyl jasmonate (MeJA) phenocopied the stem elongation of Zeo1.b, and that Zeo1.b itself was hypersensitive to inhibition by MeJA but less responsive to promotion by gibberellin. Taken together, we propose that miR172-mediated restriction of AP2 may modulate the jasmonate pathway to facilitate gibberellin-promoted stem growth during flowering

Physiological response, molecular analysis and water use efficiency of maize (Zea mays L.) hybrids grown under various irrigation regimes

With a view to study the effects of irrigation scheduling on the water use efficiency and physiological response and molecular basis of maize hybrids of different maturity groups, a field experiment was conducted at Water Management Research Center (WMRC), Belvatagi, University of Agricultural Sciences, Dharwad, India during 2010-2011 rabi season in Malaprabha Command Area’. The experiment was laid out in split plot design with three replications. The main plot comprised four irrigation levels (0.4. 0.6, and 0.8 irrigation water/cumulative pan evaporation (IW/CPE) ratio and irrigation at critical growth stages of maize) and subplots were three maize hybrids [PEEHM-5 (extra early), PEHM-2 (early) and 900 M gold (full season)] were tested. The results reveal that significantly higher grain yield (P<0.05) was at 0.8 IW/CPE ratio followed by irrigation at critical growth sages of maize. Among the maize genotypes tested, full season 900 M Gold recorded significantly greater grain yield (84.61 q ha-1) over PEHM-2 (early) and PEEHM-5 (extra-early). The moisture stress due to 0.4 IW/CPE ratio prolonged the days which reached 50% anthesis and 50% silking thus widening the anthesis-silking interval. Significant positive correlations (P<0.05) of maize grain yield with 100 seed weight (r=0.81), cob length (r=0.83), harvest index (r=0.82) and water-use efficiency (WUE; r=0.61) were found. The RWC decreased significantly (P<0.05) from 82.53 to 75.24% with increasing moisture stress on account of variations in the availability of soil moisture in the crop root zone. WUE was significantly low (P<0.05) in 0.8 IW/CPE ratio, despite providing more amount of water which could be attributed to a greater use of water with relatively lesser increase in yield. The present investigation showed that providing four irrigations at critical growth stages of maize hybrids followed by either three or five irrigations seem to have higher WUE. This approach could save water up to 29% with slight reduction of grain yield by 12% over providing full irrigation. Molecular analysis of three hybrids revealed the possibility of introgressing the yield enhancing traits from full season hybrid into early and extra-early hybrids, the latter clustered distinctly with each other. This strategy besides saving water helps tail-end farmers in choosing additional crop for double cropping in the command areas.Keywords: Maize hybrids, IW/CPE ratio, water use efficiency, grain yield.African Journal of Biotechnology, Vol 13(29) 2966-297

Soil-site Suitability Assessment for Major Fruit Crops in Chikkumbi-3 Micro-watershed (4D7C5O2f), Karnataka Using Remote Sensing and GIS Techniques

A research project was conducted to assess the viability of three soil series (CLK, CKB, and HNL) in the Chikkumbi-3 micro-watershed of Dharwad district, located in the Northern dry zone (Zone-3) of Karnataka. Using criteria such as texture, depth, slope, erosion, graveliness, and stoniness, ArcGIS V 10.8 was employed to classify the soils into five mapping units. The suitability of these mapping units was then evaluated for cultivating major fruit crops, including mango, lime, guava, grape, pomegranate, and sapota. The analysis revealed that the soil series Chulki (CLK), Chikkumbi (CKB) and Hanchinal (HNL) are presently not suitable for growing mango and lime due to significant limitations in physical conditions, rooting, and moisture. However, the region is deemed moderately to marginally suitable for the cultivation of guava, grape, pomegranate, and sapota. These findings serve as foundational data for identifying specific soil constraints, aiding in the development of sustainable strategies for crop production in the study area

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Not AvailableA field study was conducted on maize (Zea mays L.) crop by using raised bed land configuration and different irrigation techniques for three kharif season (2011 to 2013). The three years kharif seasons pooled results revealed that a significantly superior maize grain yield of 60.0 q ha–1, gross income of Rs 51,136 ha–1, net income of Rs 31,459 ha–1 and B:C ratio of 2.60 was obtained by irrigation level of 0.6 IW/CPE irrigation treatment. A significantly higher water use efficiency of 16.65 kg (ha-mm)–1 was observed with irrigation level at 0.4 IW / CPE and this result also at par with the 0.6 IW / CPE ratio. Planting on 120 cm raised bed treatments. Significantly superior maize grain yield of 60.7 q ha–1, gross income of Rs 52,973 ha–1 and net income of Rs 35,973 ha–1 and B:C ratio of 2.87 recorded. A higher water use efficiency of 15.85 kg (ha-mm)–1 was observed with 120 cm raised bed. The interaction between irrigation 0.6 IW / CPE ratio and 120 cm raised bed configuration treatment recorded a significantly superior grain yield of 66.26 q ha–1, gross income of Rs 52,686 ha–1, net income of Rs 36,314 ha–1 and B:C ratio of 2.65. A higher WUE of 15.47 kg (ha-mm)–1 was recorded with 120 cm raised bed and 0.6 IW / CPE ratio.Not Availabl