Nitrogen enhanced sorghum morpho-physiological activity, and antioxidant capacity

Imbalanced mineral nutrition and scant information about nitrogen (N) in plants may result in reduction in sorghum morpho-physiological activities. However, farmers use higher or lower fertilizer doses regarding sorghum growth and yield. This study was undertaken to determine the response of sorghum morpho-physiological activities to different rates of nitrogen (N) during two growing seasons of 2017 and 2018. The treatments were consisted of a factorial combination of three N levels (N1 = 0 kg N ha− 1, N2 = 150 Kg N ha− 1, and N3 = 300 kg N ha− 1) and two varieties (V1 = CFSH30, and V2 = Siyong 3180). Treatments were arranged in a randomized complete block design with three replicates. Our results found that N application (N2 and N3) significantly increased plant growth and morpho-physiological activities; leaf length increased by 2.7–8.9%, leaf width by 0.4–4.5%, plant height by 27.8–20.5%, Specific leaf weight by 4.2–10.9%, leaf weight by 18.4–17.4%, and protein contents by 39.5–117.0% compared to N1. Interestingly, higher rates of N reduced number of plants m− 2 by 42.4–24.8% but increased number of plants m− 2 weight kg− 1 by 11.6–62.8%. Moreover, compared with control, N enhanced CAT activity by 92.8-131.9%, SOD by 81.2–84.5%, and POD by 43.6–52.8% in 2017 and 2018. This study indicated that N3 significantly performed best among all treatments during the two growing seasons particularly in case of V1. Moreover, we also concluded that V1 performed better in terms of producing higher leaf width, plant height, specific leaf weight, stem weight, number of plants m2 (weight/kg− 1), protein contents, and antioxidant enzymes activity as compared to V2.

Improvements in Plant Morphology Facilitating Progressive Yield Increases of japonica Inbred Rice since the 1980s in East China

Grain yield was greatly increased during the genetic improvement of japonica inbred rice since the 1980s in Jiangsu, east China; thus, an improved plant morphology should be expected, considering that plant morphology is a decisive factor determining grain yield. Twelve representative japonica inbred rice released from 1983 to 2013 were grown in the same fields in 2019 and 2020. Grain yield increased (p < 0.01) at 63.3 kg ha−1 year−1 across 2 years among rice cultivars released in different periods. The genetic improvement in grain yield was associated with increased spikelets per panicle. Single panicle weight, number of primary and secondary branches, and number of grains on primary and secondary branches were all increased with a year of release. Generally, the width of top three leaves positively correlated (while angle of top three leaves and light extinction coefficient negatively) correlated (p < 0.01) with year of release. Leaf area per tiller and leaf area index at heading and maturity, specific leaf weight, leaf photosynthetic rate, and SPAD values after heading were all increased linearly with year of release. Plant height exhibited a positive (p < 0.01) trend with year of release, as well as stem weight per tiller and K and Si concentrations of stem. Spikelets per panicle, width of top three leaves, plant height, and leaf area index, and specific leaf weight after heading positively correlated (while angle of top three leaves and light extinction coefficient negatively) correlated (p < 0.01) with grain yield and single panicle weight. Our results suggested that modern japonica inbred rice exhibited expanded sink size by spikelets per panicle, higher leaf area through leaf width, optimized leaf photosynthetic capacity, lower leaf angle and light extinction coefficient, and enhanced stem strength. These improved plant morphologies facilitated yield increases of japonica inbred rice since the 1980s in east China.

Genetic variability studies in amaranthus (Amaranthus spp.)

An investigation was carried out to estimate the nature and extent of genetic variability​ ​among twenty Amaranthus genotypes (Amaranthus spp.) under a randomized block designduring the year 2019-20. The phenotypic coefficient of variation was higher than the genotypic​ ​coefficient of variation for all the traits. High genotypic coefficient of variation (GCV) and​ ​phenotypic coefficient variation (PCV) was observed for leaf area, leaf area index, leaf area​ ​duration, AGR, dry weight of leaf per plant, specific leaf weight, speed of germination,​ ​chlorophyll content and ascorbic acid (vitamin C). Moderate GCV and PCV were observed​ ​for leaf length, leaf width, petiole length, dry weight of stem per plant, leaf: stem ratio and​ ​foliage yield per plant. The high estimates of heritability coupled with higher values of genetic​ ​advance as per cent mean (GAM) were observed for the parameters like test weight, speed of​ ​germination, germination percentage, seedling dry matter, seedling vigour index-1, seedling​ ​vigour index-2, plant height, leaf length, leaf width, leaf area, leaf area index, leaf area​ ​duration, AGR, specific leaf weight, stem weight per plot, dry weight of leaf, dry weight of​ ​stem, leaf: stem ratio, foliage yield per plant, chlorophyll, ascorbic acid and beta- carotene​ ​content which indicates the predominance of additive gene action. Arka Arunima,​ ​Chikmagalur local, IC-551486, IC-551494 and IC-551466 recorded high foliage yield per​ ​plot and these can be utilized in further breeding programmes.

Growth and Productivity of ‘Consort’ Black Currant Grown under Varying Levels of Artificial Shade

The shade tolerance of black currants (Ribes nigrum cv. Consort) was studied by measuring the growth and productivity of mature plants in the field for three seasons under full sun or artificial shade netting in Urbana, IL. Shade treatments reduced photosynthetically active radiation (PAR) from 37% to 83%. Yield was not reduced in shade levels up to 65% but decreased by as much as 66% under 83% shade. Shade had minimal effect on stem rejuvenation in the first 2 years, but reduced rejuvenation in the third year from 14 new stems in full sun to eight new stems in 83% shade. Stem diameter decreased 8% to 19% with 83% shade, whereas no changes were observed in up to 65% shade. Plant height increased 5% to 8% from open sun to 83% shade. Specific leaf weight decreased and leaf area increased with shade. Powdery mildew severity increased with shade, and disease-resistant cultivars should be considered for understory crops. Our results indicate that growth and productivity of black currants can be maintained in moderate shade but shade levels beyond 65% will significantly reduce agronomic performance.

Agro-physiological assessment of weed interference in groundnut (Arachis hypogea L.) at Sub-Himalayan hill region of Meghalaya

Field experiment was carried out during Kharif and Rabi seasons of 2016-17 at the mid altitudes of Meghalaya in the precincts of Sub Himalayan hill region to assess and quantify the extent of weed interference on growth and physiology of groundnut in both seasons of the year. Crop physiological parameters viz., LAI, CGR, RGR, NAR, SPAD value, leaf thickness, specific leaf area, specific leaf weight and partitioning efficiency which are key for determining growth and yield of crop were documented periodically. The highest values of all the physiological attributes were found in weed free check, and lowest with weedy check. As weeds, biological agents with similar cellular and plant structure equally affect the crop in all sectors of growth and reproduction but it is not shared uniformly across all stages of crop growth but with increasing period of weed interference decrease the extent of damage to crop plants.

Evaluation of agronomic performances of rainfed barley double-haploids (DHs) lines under semi-arid conditions

Karkour L, Fenni M, Ramla D, Gaad D, Benbelkacem A. 2019. Evaluation of agronomic performances of rainfed barley double-haploids (DHs) lines under semi-arid conditions. Biodiversitas 20: 1398-1408. Sixty-six doubled-haploid (DHs) barley lines derived from F2 plants of three bi-parental single crosses, between the local variety (Tichdrett) and three introduced genotypes (Express, Plaisant, and Exito) were evaluated in 2017 for agronomic performance. The experiment was undertaken at two locations under rainfed conditions in semi-arid zone of Algeria in a randomized block design with three replications. Each line was scored for fifteen quantitative traits: number of days to heading, thousand grains weight, number of grains per spike, spikes number per m2, plant height, spike length, leaf relative water content, awn length, peduncle length, spike weight, grain weight per spike, leaf area, specific leaf weight, grain yield and harvest index. The results indicated that the presence of highly significant genotype effect for all traits except for leaf area and highly significant environment effect for all characters, except spikes number per m2and awns length. Genotype x environment interaction was highly significant for all traits, except specific leaf weight and leaf area. Significant positive correlation between the twelve agronomic traits, ranging from 0.45 to 0.87, were observed among the number of grains per spike, thousand grains weight, the number of spikes per m2, yield of grains and harvest index. The principal component analysis showed that four components could describe 72% of total variances. Cluster analysis divided all genotypes studied into three cluster groups. Overall, results of agronomic parameters and those related to the biotic and abiotic stresses will be used for better identifying this germplasm and better-directing studies of genetic improvement.

The Growth and Development of ‘Mini Chal’ Tomato Plug Seedlings Grown under Various Wavelengths Using Light Emitting Diodes

This study aimed to determine the effects of various light qualities (green (G), ultraviolet-A (UV-A), and far-red (Fr)) on the growth and development of tomato plug seedlings. The ‘Mini Chal’ tomato (Solanum lycopersicum L.) seedlings were used as the plant material to which various light qualities were supplied. Fluorescent lamp (FL), combined FL and diniconazole (Dini), and R3B7 (red (R):blue (B) = 30:70) were used as the control. The different light treatments for this experiment were as follows: two G light ratios added to R3B7 (G20 and G40), three UV-A light intensities added to R3B7 (UV 0.4, UV 0.6, and UV 0.8), and three Fr light ratios added to R3B7 (Fr1, Fr2, and Fr3). Plants grown in UV 0.4 and Dini were the shortest, followed by plants grown in R3B7. R3B7 induced higher specific leaf weight than G, UV-A, and Fr did. The position of the first flower cluster was the highest for plants in FL and Fr1, and the lowest for plants in R3B7 and UV 0.6. In conclusion, different light treatments heavily affected the growth and development of ‘Mini Chal’ tomato seedlings. R3B7 was the most effective light treatment for producing high quality seedlings in a closed-type plant production system that develop well after transplanting.

Provenance Variation in Pinus palustris Foliar δ13C

Longleaf pine forests are currently being restored in the southern U.S. To aid in the deployment of longleaf pine under current and future climate conditions, we tested the hypothesis that genetic variability in foliar carbon isotope composition (δ13C) exists in this species. Foliar δ13C, height and diameter were measured at ages of 5 and 6 years, and needle length, specific leaf weight (SLW) and foliar N concentration were measured at an age of 6 years in 16 longleaf pine families representing a large portion of the species’ range. Families were grown in common garden tests in North Carolina and Mississippi and grouped for analysis into six provenances based on climate, soils, and discontinuities in the species’ range. No genetic by environment interactions were observed. Greater foliar δ13C was observed in trees from the provenance consisting of the Piedmont and Montane Uplands than from the provenances representing the western and eastern Gulf Coastal Plains. Foliar δ13C was not significantly correlated to height at age 6, suggesting that it may be possible to select for improved foliar δ13C without sacrificing growth. These results represent a first step in identifying potential genetic variation in leaf water use efficiency and drought tolerance of longleaf pine.