Differential Maize Yield Hybrid Responses to Stand Density Are Correlated to Their Response to Radiation Reductions Around Flowering

Altered stand density affects maize yields by producing changes in both numerical yield components, kernel number per plant (KNP), and kernel weight (KW). Kernel number is determined by the accumulation of ear biomass during the flowering period, whereas KW is determined by the sink potential established during flowering and the capacity of the plant to fulfill this potential during effective grain filling. Here, we tested if different short shading treatments during different stages around flowering can help discriminate genotypic differences in eco-physiological parameters relevant for maize stand density yield response and associated yield components. Our specific objectives were to: (i) identify hybrids with differential shading stress response, (ii) explore shading effects over eco-physiological parameters mechanistically related to KNP and KW, and (iii) test if shading stress can be used for detecting differential genotypic yield responses to stand density. The objectives were tested using four commercial maize hybrids. Results indicated that KNP was the yield component most related to yield changes across the different shading treatments, and that the specific shading imposed soon after anthesis generated the highest yield reductions. Hybrids less sensitive to shading stress were those that reduced their plant growth rate the least and the ones that accumulated more ear biomass during flowering. Genotype susceptibility to shading stress around flowering was correlated to stand density responses. This indicated that specific shading stress treatments are a useful tool to phenotype for differential stand density responses of commercial hybrids.

Cluster-Zone Leaf Removal and GA3 Application at Early Flowering Reduce Bunch Compactness and Yield per Vine in Vitis vinifera cv. Pinot Gris

Compact bunches have been often associated with higher susceptibility to Botrytis cinerea and therefore reduction in berry quality in grapevine. The objective of this study was to evaluate three management methods (early leaf removal, gibberellic acid, and their combination) for reducing bunch compactness in Vitis vinifera cv. Pinot gris trained in two different training systems with contrasting vigor (Guyot and pergola). Treatments were applied at BBCH 62 or BBCH 65 and yield components, total soluble solids, fruit set, and bunch compactness parameters were evaluated. Both treatments individually reduced berry number, mean bunches weight and bunches compactness as well as yield per vine when compared to control-untreated vines. However, no major differences were observed when both the treatments were applied in combination for Guyot or pergola although a higher reduction in yield was detected for Guyot and a significant increase in total soluble solids was observed in pergola. Our study suggests that intense leaf removal and gibberellic acid applied at early flowering can help reducing bunch compactness in Pinot gris and showing it in two training systems. In particular, leaf removal represents a valuable alternative to plant growth regulators (i.e., gibberellic acid) as applicable in organic viticulture.

The Effect of Cultivation Practices on Agronomic Performance, Elemental Composition and Isotopic Signature of Spring Oat (Avena sativa L.)

The present study investigated the effects of cultivation practices on grain (oats) yield and yield components, such as straw yield, harvest index, thousand kernel weight, and plant lodging. In addition, multi-element composition and isotopic signature (δ13C, δ15N) of the oat grains were studied. The spring oat cultivar ‘Noni’ was grown in a long-term field experiment during 2015–2020, using three management practices: control without organic amendment, incorporation of manure every third year and incorporation of crop residues/cover crop in the rotation. Synthetic nitrogen (N) (0, 55, 110 and 165 kg/ha) was applied during oat development in each system. Multi-element analysis of mature grains from two consecutive years (2016 and 2017) was performed using EDXRF spectroscopy, while stable isotope ratios of carbon (C) and nitrogen (N) were obtained using an elemental analyzer coupled to an isotope ratio mass spectrometer (EA/IRMS). The results show how cultivation practices affect yield components and isotopic and elemental signatures. Increasing the N rate improved both the oat grain and straw yields and increased susceptibility to lodging. The results show how the elemental content (Si, Ca, Zn, Fe, Ti, Br and Rb) in the oat grains were influenced by intensification, and a noticeable decrease in elemental content at higher N rates was the result of a dilution effect of increased dry matter production. The mean δ15N values in oat grains ranged from 2.5‰ to 6.4‰ and decreased with increasing N rate, while δ13C values ranged from −29.9‰ to –28.9‰. Based on the δ15N values, it was possible to detect the addition of synthetic N above an N rate of 55 kg/ha, although it was impossible to differentiate between different management practices using stable isotopes.

Green entrepreneurship in India

The experiment was conducted to evaluate the adaptability of newly released papaya varieties at Chano Mille research site of Arba Minch Agricultural Research Center during 2019-2020 cropping seasons. The three hermaphrodite papaya varieties namely; Braz-HS1, Koka-HM1 and Meki-HL1 were used for the study and laid-out in a Randomized Complete Block Design in three replications. Data on yield and yield components were collected and analyzed by using analysis of variance (ANOVA) through Statistical Analytics System software. The ANOVA results revealed that there were significant variations among papaya varieties for the studied parameters. Significantly, the highest number of fruits plant-1, number of leaves and fruit yield were obtained from Braz-HS1 papaya variety. The fruit yield of Braz-HS1 variety was 46% higher than that of Koka-HM1. In general, Braz-HS1 papaya variety performed (in terms of number of fruits and fruit yield) better than the rest two varieties. Thus, Braz-HS1 papaya variety could be recommended for the papaya growers in the study area and vicinity with similar agro-ecology. Int. J. Agril. Res. Innov. Tech. 11(2): 72-75, Dec 2021

Evaluation of improved hermaphrodite papaya (Carica papaya L.) varieties at Arba Minch, Southern Ethiopia

The experiment was conducted to evaluate the adaptability of newly released papaya varieties at Chano Mille research site of Arba Minch Agricultural Research Center during 2019-2020 cropping seasons. The three hermaphrodite papaya varieties namely; Braz-HS1, Koka-HM1 and Meki-HL1 were used for the study and laid-out in a Randomized Complete Block Design in three replications. Data on yield and yield components were collected and analyzed by using analysis of variance (ANOVA) through Statistical Analytics System software. The ANOVA results revealed that there were significant variations among papaya varieties for the studied parameters. Significantly, the highest number of fruits plant-1, number of leaves and fruit yield were obtained from Braz-HS1 papaya variety. The fruit yield of Braz-HS1 variety was 46% higher than that of Koka-HM1. In general, Braz-HS1 papaya variety performed (in terms of number of fruits and fruit yield) better than the rest two varieties. Thus, Braz-HS1 papaya variety could be recommended for the papaya growers in the study area and vicinity with similar agro-ecology. Int. J. Agril. Res. Innov. Tech. 11(2): 69-71, Dec 2021

Effect of Ethephon Application on Seed Yield and Yield Components of Two Faba Bean (Vicia faba L.) Cultivars

The aim of present study was to determine the effects of different ethephon doses on grain yield and yield components of two faba bean cultivars. The experiment was established in 2019/2020 and 2020/2021 cropping season at Research Area of Field Crops Department, Agriculture of Faculty, Cukurova University Adana, Turkey. The field experiment was laid out in randomized complete blocks design (RCBD) with three replications on the basis split plot design with cultivars (Luz de Otono and Histal) in main plots and ethephon doses (0, 500, 1000, 1500 g ha-1) in sub plots. Plant height (cm), branches per plant, pods per plant, seeds per plant, seed yield per plant (g), 100 grain weight (g), seed yield (kg ha-1) were investigated. Differences among the cultivars and ethephon applications were significant for seed yield and it varied from 1782 to 3388 kg ha-1 in the mean of the years. Seed yield also decreased with increasing ethephon doses. Seed yield was higher in 2019/2020 (3355 kg ha) than 2020/2021 (1841 kg ha-1) where low rainfed and high temperature. The present results suggested that ethephon applications at inititation of flowering were not useful for seed production of faba bean.

Genetic Correlation Between Fe and Zn Biofortification and Yield Components in a Common Bean (Phaseolus vulgaris L.)

Common bean (Phaseolus vulgaris L.) is the most important legume for direct human consumption worldwide. It is a rich and relatively inexpensive source of proteins and micronutrients, especially iron and zinc. Bean is a target for biofortification to develop new cultivars with high Fe/Zn levels that help to ameliorate malnutrition mainly in developing countries. A strong negative phenotypic correlation between Fe/Zn concentration and yield is usually reported, posing a significant challenge for breeders. The objective of this study was to investigate the genetic relationship between Fe/Zn. We used Quantitative Trait Loci (QTLs) mapping and Genome-Wide Association Studies (GWAS) analysis in three bi-parental populations that included biofortified parents, identifying genomic regions associated with yield and micromineral accumulation. Significant negative correlations were observed between agronomic traits (pod harvest index, PHI; pod number, PdN; seed number, SdN; 100 seed weight, 100SdW; and seed per pod, Sd/Pd) and micronutrient concentration traits (SdFe and SdZn), especially between pod harvest index (PHI) and SdFe and SdZn. PHI presented a higher correlation with SdN than PdN. Seventy-nine QTLs were identified for the three populations: 14 for SdFe, 12 for SdZn, 13 for PHI, 11 for SdN, 14 for PdN, 6 for 100SdW, and 9 for Sd/Pd. Twenty-three hotspot regions were identified in which several QTLs were co-located, of which 13 hotpots displayed QTL of opposite effect for yield components and Fe/Zn accumulation. In contrast, eight QTLs for SdFe and six QTLs for SdZn were observed that segregated independently of QTL of yield components. The selection of these QTLs will enable enhanced levels of Fe/Zn and will not affect the yield performance of new cultivars focused on biofortification.