Allelopathic Allelopathic impact of sorghum on weed management, yield and quality of maize under different seed rates

A field study was carried out to estimate the allelopathic potential of sorghum immature and mature plant extracts under various seed rates on weeds density and yield of maize cultivar Dadu Maize-I. The experiment contained of different weed control practices i.e., control (No weeding), various levels of sorghum immature and mature plant extracts, herbicides and hand weeding under various seed rates (20, 25, 30 & 35 kg per ha). The analysis of variance showed that various weed control practices demonstrated substantial decrease in weeds and caused increase in kernel yield over control. The application of sorghum immature extract @ 15 L per ha in combination with herbicide (Mesotrione Atrazine) @ 1.0 L per ha decreased effectively weed density (m-2) and dry biomass (g m-2) and resultantly produced superior growth and yield traits particularly kernel yield (t per ha) of maize. Sorghum mature plant extract @ 15 L per ha in integration with herbicide (Mesotrione Atrazine) @ 1.0 L per ha ranked 2nd in effectiveness of controlling weeds as well as increasing maize kernel yield (t per ha). As much as effect of seed rates is concerned, the least weed density (m-2) and greatest kernel yield (t per ha) were noticed in seed rate 35 kg per ha but optimal kernel yield (t per ha) was record in seed rate 30 kg per ha. Hence, the results suggested that combination of plant extracts and herbicide at reduced doses controlled weeds efficiently and optimum enhancement in kernel yield of maize was noticed at seed rate 30 kg per ha.

Microclimate Modification through Groundnut-Pigeon Pea Intercropping System and its Effect on Physiological Responses, Disease Incidence and Productivity

Background: Groundnut (Arachis hypogaea) is the predominant leguminous oilseed crop of India which has turned out to be a sensitive victim to climate change episodes like rising CO2 levels, erratic rainfall pattern, high temperature and moisture stress leaving deleterious imprints in physiology, disease resistance, fertility and productivity. Globally climate change is anticipated to pull down groundnut productivity by 11-25%. Agronomic manipulations like altered time of sowing, intercropping and irrigation management helps in microclimate modification towards reaping higher productivity and economic returns in groundnut. Methods: Field experiments were conducted during 2019-2021 on sandy clay loam soil (Fluventic Ustropept) in a Randomized Block Design with three factors viz., differential cropping systems (sole groundnut, groundnut + red gram intercropping), rainfed and irrigation systems and differential sowing windows (Second fortnight of June, first and second fortnights of July). Growth parameters, physiological traits viz., photosynthetic rate, transpiration rate, stomatal conductance, canopy temperature and light interception, incidence of foliar diseases viz., leaf spot and rust; soil borne disease viz., stem rot, root rot and productivity of groundnut were recorded at critical crop growth stages. Result: Canopy temperature was higher in sole groundnut system while light interception was higher in groundnut - redgram intercropping system, however system productivity did not register statistical superiority between the cropping systems. Irrigated system exerted its influence over rainfed system in terms of pod and kernel yield of groundnut. Sowing of groundnut during second fortnight of June was beneficial than July sowing in pod and kernel yield of groundnut due to uniform distribution of rainfall during the growth and reproductive phases of crop. Although differential cropping systems did not register their impact on disease incidence of groundnut, irrigated system and first sowing windows recorded minimum incidence of root rot, stem rot, early leaf spot, late leaf spot and rust diseases compared to rainfed system and July sowing.

Transplanting and the addition of boron in sweet corn (Zea mays L. group saccharate) production

Introduction. Low seedbed temperatures at the planting and the direct sowing method can reduce the sweet corn germination. Transplanting may offer optimum environmental conditions for seed germination, early crop maturity, and increase sweet corn (Zea mays L. group saccharata) productivity. Boron deficiency depresses sweet corn yield through male sterility. Objective. To evaluate the effect of transplanting and the addition of boron in sweet corn production. Materials and methods. A field experiment was conducted from March 19 to June 20, 2020 at the Research Station of Horticulture Department and Landscape Gardening Architecture, University of Diyala, Baqubah, Iraq. Direct sowing and transplanting, and foliar application of boron at 0, 50, or 75 mg L-1 was evaluated to determine effects on the yield, the yield components, and water use efficiency of sweet corn cultivars: Roi Soleal, Seker misir, and Succar. Results. The cv. Seker Misir matured faster (57.5 days), had wider ears (4.53 cm), more kernel rows (16.0), the highest kernel yield (6.00 t ha-1), and a higher water use efficiency (WUE) (2.85 kg m-3). The cv. Succar had the longest ears (18.48 cm) and the heaviest fresh ears (251 g). Transplanting hastened the time to maturity (54.18 days), and produced the longest ears (17.91 cm), widest ears (4.52 cm), most kernel rows (15.96), heaviest fresh ears (229 g), the highest kernel yield (5.56 t ha-1), and the highest WUE (2.64 kg m-3). The 50 mg L-1 fertilizer treatment produced the longest ears (17.61 cm), widest ears (4.58 cm), more kernel rows (16.61), the highest kernel yield (5.64 t ha-1), and the highest WUE (2.68 kg m-3). The least time to maturity (57.72 days) and heaviest fresh ears (232 g) occurred with 75 mg L-1 of boron fertilizer. Conclusion. The use of 50 mg L-1 boron, as a foliar fertilizer, appears to be, next to the transplanting method, suitable for the cultivation of sweet corn plants to increase productivity and WUE.

Genetic Variability, Character Association and Path Analysis for Pod Yield and its Component Characters in Groundnut [Arachis hypogaea (L.)]

Background: Groundnut is an important oilseed crop in the India. The groundnut kernels serve as a rich source of edible oil (48-50%) and quality protein (25-28%). In crop improvement programme, availability of sufficient genetic variability is of immense importance. The knowledge of nature and magnitude of genetic variance controlling yield and yield components is a prerequisite for improvement of yield in any crop. Methods: The present investigation was undertaken to assess the genetic variability and character associations for pod yield and component characters in 45 genotypes of groundnut. The genotypes were raised in randomized complete block design with three replications during kharif 2019 at SKNAU, Jobner (Rajasthan). Result: The analysis of variance revealed significant differences among the genotypes for all the characters studied indicating presence of wide genetic variation for different characters. In the present investigation, high genetic advance coupled with high heritability and GCV was observed for biological yield per plant, 100-kernel weight, kernel yield per plant, dry pod yield per plant and pods per plant which indicated prevalence of additive gene action in their expression and these traits possessed high selective value. Kernel yield per plant, pods per plant and biological yield per plant exhibited significantly positive correlation with dry pod yield per plant both at genotypic and phenotypic levels, while shelling percentage at genotypic level only. Three characters viz., kernel yield per plant, pods per plant and biological yield per plant could be considered as direct selection parameters for yield improvement in groundnut because they exerted positive direct effect on dry pod yield per plant.

Impacts of environmental conditions, and allelic variation of cytosolic glutamine synthetase on maize hybrid kernel production

Cytosolic glutamine synthetase (GS1) is the enzyme mainly responsible of ammonium assimilation and reassimilation in maize leaves. The agronomic potential of GS1 in maize kernel production was investigated by examining the impact of an overexpression of the enzyme in the leaf cells. Transgenic hybrids exhibiting a three-fold increase in leaf GS activity were produced and characterized using plants grown in the field. Several independent hybrids overexpressing Gln1-3, a gene encoding cytosolic (GS1), in the leaf and bundle sheath mesophyll cells were grown over five years in different locations. On average, a 3.8% increase in kernel yield was obtained in the transgenic hybrids compared to controls. However, we observed that such an increase was simultaneously dependent upon both the environmental conditions and the transgenic event for a given field trial. Although variable from one environment to another, significant associations were also found between two GS1 genes (Gln1-3 and Gln1-4) polymorphic regions and kernel yield in different locations. We propose that the GS1 enzyme is a potential lead for producing high yielding maize hybrids using either genetic engineering or marker-assisted selection. However, for these hybrids, yield increases will be largely dependent upon the environmental conditions used to grow the plants.

Pollen limitation and xenia effects in a cultivated mass-flowering tree, Macadamia integrifolia (Proteaceae)

Background and Aims Pollen limitation is most prevalent among bee-pollinated plants, self-incompatible plants, and tropical plants. However, we have very little understanding of the extent to which pollen limitation affects fruit set in mass-flowering trees despite tree crops accounting for at least 600 million tons of the 9,200 million tons of annual global food production. Methods We determined the extent of pollen limitation in a bee-pollinated, partially self-incompatible, subtropical tree by hand cross-pollinating the majority of flowers on mass-flowering macadamia (Macadamia integrifolia) trees that produce about 200,000–400,000 flowers. We measured tree yield and kernel quality and estimated final fruit set. We genotyped individual kernels by MassARRAY to determine levels of outcrossing in orchards and assess paternity effects on nut quality. Key Results Macadamia trees were pollen limited. Supplementary cross-pollination increased nut-in-shell yield, kernel yield and fruit set by as much as 97%, 109% and 92%, respectively. The extent of pollen limitation depended upon the proximity of experimental trees to trees of another cultivar because macadamia trees were highly outcrossing. Between 84% and 100% of fruit arose from cross-pollination, even at 200 m (25 rows) from orchard blocks of another cultivar. Large variations in nut-in-shell mass, kernel mass, kernel recovery and kernel oil concentration were related to differences in fruit paternity, including between self-pollinated and cross-pollinated fruit, thus demonstrating pollen-parent effects on fruit quality, i.e. xenia. Conclusions This study is the first to demonstrate pollen limitation in a mass-flowering tree. Improved pollination led to increased kernel yield of 0.31–0.59 tons per hectare, which equates currently to higher farm-gate income of approximately US3,720–US7,080 per hectare. The heavy reliance of macadamia flowers on cross-pollination and the strong xenia effects on kernel mass demonstrate the high value that pollination services can provide to food production.

DETERMINATION OF SUITABLE WINTER CHICKPEA (CICER ARIETINUM L.) CULTIVARS UNDER KAHRAMANMARAŞ CONDITIONS

This study was conducted with the chickpea cultivars of Işık-05, Azkan, Sarı 98, Hisar, Çakır, Aydın 92, Yaşa-05, Menemen 92, Cevdetbey, Çağatay, Aksu and two local cultivars over the experimental fields of Kahramanmaraş Eastern Mediterranean Transitional Zone Agricultural Research of Institute in 2014-2015 cropping years. Experiments were conducted in randomized blocks design with 3 replications. Quality traits of plant height, the first pod height, number of branches per plant, number of pods per plant, number of kernels per plant, kernel weight per plant, kernel yield, 100-kernel weights were investigated. The differences in plant height, the first pod height, number of branches per plant, number of pods per plant, number of kernels per plant, kernel weight per plant, kernel yield and 100-kernel weight of the genotypes were found to be significant. Kernel yields of the genotypes varied between 425.40 - 267.93 kg da-1 with the greatest value from Çakır cultivar and the lowest value from Hisar cultivar.

Effects of weed management on agronomic performance and productivity of hybrid maize (Zea mays L.)

The yield loss as a result of weed infestation is a major problem in maize fields. Hence, this research meant to examine the impacts of weed chemical control on maize growth and yield. The design of experiment was randomized complete block, and comprised 10 treatments viz., T1 (Control, weedy check), T2 (Weed free), T3 (Atrazine 1.5 kg ha-1 pre-emergence), T4 (Atrazine 750 g ha-1 + Pendimethalin 750 ml ha-1 pre-emergence), T5 (Atrazine 1.5 kg ha-1 followed by 2,4-D amine 0.4 kg ha-1 at 25 days after sowing as Post-emergence), T6 (Halosulfuron 67 g ha-1 at 25 DAS), T7 (Atrazine 1.5 kg ha-1 pre-emergence followed by Halosulfuron 90 g ha-1 25 days after sowing), T8 (Tembotrione 120 g ha-1 Post-emergence at 25 days after sowing), T9 (Pendimethalin 1000 ml ha-1 pre-rise fb Atrazine 750 g ha-1 + 2,4-D amine 0.4 kg ha-1 at 25 days after sowing as Post-emergence) and T10 (Atrazine 1.5 kg ha-1 pre-emergence followed by Tembotrione 120 g ha-1 Post-emergence at 25 days after sowing) with 3 replicates. The results showed that among other treatments, T10 recorded highest number of kernels per row (36.18), number of kernel cob-1 (499.12) and kernel weight cob-1 (136.97 g). A higher plant height (172.19 cm), leaf area (396.6 cm2 plant-1), dry matter accumulation (211.37 g plant-1), kernel yield (6.7 t ha-1) and stover yield (11.6 t ha-1) were found with weed free check plot which is on par with T10 treatment which brought about a higher value of plant height (162.93 cm), dry weight accumulation (205.7 g plant-1), leaf area (384.3 cm2 plant-1), kernel yield (6.5 t ha-1) and stover yield (11.4 t ha-1). In the meantime, T9 treatment reasonably increased kernel yield (6.2 t ha-1) and stover yield (11.0 t ha-1). It shows that application of herbicides as pre-emergence followed by post-emergence, such as T10 treatment could be a good method for weed control in maize fields.