Panicle Formation Research Articles

Estimation of Nitrogen Content of Rice Crops Using Sentinel-2 Data

Nitrogen (N) is one of the most essential nutrients for rice crops. Farmers generally provide Nitrogen requirements in rice through fertilization, but the fertilization process is only based on an estimation without calculating the amount needed first. However, neither insufficient nor excessive nitrogen content is good for rice crops, and the nitrogen needs of rice crops are different at each growth stage. The nitrogen requirement in the generative phase is relatively high because the process of panicle formation and grain filling occurs at this stage. Several methods can be used to monitor nitrogen content in rice, one of which is using remote sensing methods. With the vegetation index approach, the nitrogen content of rice plants is estimated through data analysis of the light spectrum reflected by the leaf. Sentinel-2 satellite imagery was used in this research, and several vegetation indexes such as OSAVI, GNDVI, and SRRE were applied to form an estimation model using the regression method. From the results, three vegetation indexes positively correlate with nitrogen content in rice crops. The SRRE index gives the highest correlation coefficient value of 0.692, while the correlation coefficient value for GNDVI is 0.498, and OSAVI is only 0.470. The estimation map of the nitrogen content of rice crops was obtained based on the estimation model made by linear regression between SPAD-based nitrogen content data and the best vegetation index using the SRRE index. The analysis shows that the nitrogen content of rice plants estimated in the paddy fields of Karangjati Subdistrict is dominated by nitrogen values with optimum classification.

Optimizing Nitrogen Dosage and Planting Density to Improve Japonica Rice Yield

In Northeast China’s black soil rice cropping area, nitrogen (N) application is lower than in the south, yet excessive N fertilizer use persists, particularly in base fertilizers. This study aimed to assess the impact of reduced N and increased planting density on rice yields and photosynthetic matter production. From 2019 to 2020, a field split-plot experiment was conducted with two N rates (conventional N, CN: 120 kg ha−1 and reduced basal N, RN: 108 kg ha−1) and two planting densities (D1: 33.3 × 104 hills ha−1 and D2: 27.8 × 104 hills ha−1) using the rice varieties Kongyu131 (KY131) and Kendao24 (KD24). The results showed that RN increased the effective panicle formation rate but decreased the tiller numbers, dry matter accumulation, stems/sheaths transport capacity, leaf photosynthetic capacity, and yield by 2.67% compared to CN. D1 significantly boosted the dry matter accumulation, stems/sheaths transport, effective panicles, grains per square meter, and yield by 8.26% compared to D2. Interaction analysis revealed that RN under D2 conditions reduced the effective panicle percentage, harvest index, filled grain number, leaf area index (LAI), crop growth rate (CGR), and net assimilation rate (NAR) but increased the seed setting rate and 1000-grain weight. Under D1, RN reduced the LAI, CGR, and NAR at the tillering and heading stages but increased the NAR post-heading. Compared to CND2, RND1 increased the biomass, stems/sheaths transport, LAI, CGR, NAR, seed setting rate, 1000-grain weight, panicle numbers, and filled grains per square meter, compensating for the lower harvest index and effective panicle rate, achieving a 5.36% yield increase. KD24 outperformed KY131 in yield improvement. In summary, using 108 kg ha−1 with a planting density of 33.3 × 104 hills ha−1 promotes tillering, enhances photosynthetic substance production stems/sheaths dry matter transport, and increases rice yields.

NZVI@BC as a Soil Amendment and Its Effects on Potted Rice Growth and Soil Properties

This study investigated the effects of nano zero-valent iron-modified biochar (nZVI@BC) as a soil amendment on potted rice growth, soil properties, and heavy metal dynamics. Seven treatments with varying amounts of soil conditioner, biochar, and nZVI@BC were applied to potted rice. Results showed that nZVI@BC application significantly improved rice agronomic traits, with the 15 g·kg−1 treatment increasing the panicle formation rate by 15% and 100-grain weight by 8% compared to the control. Soil fertility was enhanced, with available phosphorus increasing from 137 to 281 mg·kg−1 in the most effective treatment. Heavy metal analysis revealed that nZVI@BC application did not increase soil heavy metal content, with Cd levels remaining below 0.3 mg·kg−1 across treatments. Notably, the 10 g·kg−1 nZVI@BC treatment showed potential for slight Cd immobilization, reducing its concentration from 0.32 to 0.26 mg·kg−1. Microbial community analysis showed that nZVI@BC altered soil microbial diversity and composition, with the 10 g·kg−1 treatment resulting in the highest fungal diversity (Chao1 index: 294.219). The relative abundance of the beneficial fungal class Agaricomycetes increased from 40% to 55% with optimal nZVI@BC application. These findings suggest that nZVI@BC has potential as an effective soil amendment for improving rice cultivation while maintaining soil health, microbial diversity, and potentially mitigating heavy metal contamination.

Assessment of the impact of observations at Nainital (India) and Comilla (Bangladesh) on the CH4 flux inversion

Methane emission in South Asia is poorly understood due to a lack of observations, despite being a major contributor to methane emissions globally. We present the first results of atmospheric CH4 inversions using air samples collected weekly at Nainital, India (NTL), and Comilla, Bangladesh (CLA), in addition to surface background flask measurements by NOAA, CSIRO and AGAGE using the MIROC4-ACTM. Our simulations span from 2000 to 2020 (considering the fixed “edge” effect), but the main analysis period is 2013–2020, when both the NTL and CLA datasets are available. An additional flux uncertainty reduction of up to 40% was obtained (mainly in the northern part of the Indian subcontinent), which enhanced our confidence in flux estimation and reaffirmed the significance of observations at the NTL and CLA sites. Our estimated regional flux was 64.0 ± 4.7 Tg-CH4 yr−1 in South Asia for the period 2013–2020. We considered two combinations of a priori fluxes that represented different approaches for CH4 emission from rice fields and wetlands. By the inversion, the difference in emissions between these combinations was notably reduced due to the adjustment of the CH4 emission from the agriculture, oil and gas, and waste sectors. At the same time, the discrepancy in wetland emissions, approximately 8 Tg-CH4 yr−1, remained unchanged. In addition to adjusting the annual totals, the inclusion of NTL/CLA observations in the inversion analysis modified the seasonal cycle of total fluxes, possibly due to the agricultural sector. While the a priori fluxes consisted of a single peak in August, the a posteriori values indicated double peaks in May and September. These peaks are highly likely associated with field preparation for summer crops and emissions from rice fields during the heading stage (panicle formation). The newly incorporated sites primarily exhibit sensitivity to the Indo-Gangetic Plain subregion, while coverage in southern India remains limited. Expanding the observation network is necessary, with careful analysis of potential locations using back-trajectory methods for footprint evaluation.

Patterns of photosynthetic indicators of giant miscanthus in the Right Bank Forest Steppe of Ukraine

Purpose. To establish the influence of the elements of cultivation technology on the formation of photosynthetic indicators in giant miscanthus. Methods. The research was conducted at the Bila Tserkva Experimental Breeding Station of the Institute of Bioenergy Crops and Sugar Beet of the National Academy of Agrarian Sciences (Kyiv region) in 2019–2022. Miscanthus gigantheus variety ‘Osinnii zoretsvit’ was grown according to a three-factor field experiment design: factor A: inoculation: 1) without inoculation; 2) Azophosphorin, 1.0 l/ha; factor B: application of adsorbent: 1) without adsorbent; 2) MaxiMarin granulated, 30 kg/ha; factor B: foliar feeding: 1) without feeding; 2) Humifild, 50 g/ha; 3) Humifild, 50 g/ha + AminoStar, 1.0 l/ha. Results. The highest leaf area in the experiment was formed in the treatments with inoculation using Azophosphorin together with the adsorbent and foliar application of potassium humate (Humifild) + antistressant AminoStar. Under these conditions, leaf area in the panicle formation stage of miscanthus was 60.7 thousand m²/ha. Inoculation with Azophosphorin had a positive effect on the photosynthetic potential of plantations, increasing the indicators by 0.19 thousand m²/ha × day in 2020, by 0.24 thousand m²/ha × days in 2021 and by 0.20 thousand. m²/ha × day in 2022. Application of MaxiMarin granulated adsorbent also contributed to an increase in photosynthetic potential: by 0.18 thousand m²/ha × day in 2020, by 0.21 thousand m²/ha × day in 2021 and by 0.18 thousand m²/ha × day in 2022. Under the combined effect of factors (inoculation + hydrogel) and treatment of plantations with potassium humate (Humifild), 50 g/ha + antistressant AminoStar, 1.0 l/ha maximum indicators of photosynthetic potential were achieved: 3.26 thousand m²/ha × day in 2020, 4.23 thousand m²/ha × day in 2021 and 3.58 thousand m²/ha × day in 2022. NPP, on average in the experiment was 2.16 g/m² × day in 2020, 4.99 g/m² × day in 2021 and 5.03 g/m² × day in 2022. Despite loss of sprouts in 2022, the giant miscanthus plants were able to regrow and form a high NPP. The use of inoculation with Azophosphorin increased the NPP by 0.19 g/m² × day in 2020, by 0.43 g/m² × day in 2021, and by 0.49 g/m² × day in 2022. Application of MaxiMarin granulated adsorbent increased NPP by 0.13 g/m² × day in 2020, by 0.34 g/m² × day in 2021 and by 0.62 g/m² × day in 2022. Under the combined effect of factors (inoculation with Azophosphorin and MaxiMarin granulated hydrogel) high NPP indicators were achieved: 2.34 g/m² × day in 2020, 5.40 g/m² × day in 2021 and 5.56 g/m² × day in 2022. No significant contribution of the factor of foliar application of humates and amino acids was found. Conclusions. The data obtained in the experiment can be used to optimize the elements of the cultivation technology for giant miscanthus in the Right Bank Forest Steppe of Ukraine in order to increase the productivity of plantation.

Effects of plant density and nitrogen splitting on grain yield and nitrogen uptake in rice re-cropping

Rice (Oryza sativa L.) re-cropping has a special place in the crop rotation of rice plants in terms of increasing the efficiency of land productivity. A two-year research (2013–2014) was done with three replications to determine the best planting density and appropriate nitrogen splitting in rice re-cropping at Qaemshahr Agricultural Faculty, Mazandaran, northern Iran. For this purpose, a split plot design in RCBD format was used. Experimental factors consisted of plant density (33.3, 25, and 16 plants per sq m at intervals of 30 × 10, 20 × 20, and 25 × 25 cm2, respectively) as the main factor, and nitrogen splitting (NS1: all as a base, NS2: 1 2 base + 1 2 tillering, NS3: 1 2 base + 1 2 panicle formation, NS4: 1 3 base + 1 3 tillering + 1 3 panicle formation, and NS5: 1 3 base + 1 3 panicle formation + 1 3 end of panicle emergence) as subfactors. The results showed that the grain yield was higher for 2014 than in 2013 by 60.0%, due to increasing the number of panicles per sq m (27.2%) and the weight of 1000 grains (7.2%). The maximum grain yield was achieved at a density of 33.3 plants per sq m along with NS4 treatment. The highest straw nitrogen uptake was observed in 2013 by NS4 treatment. The maximum grain nitrogen concentration, nitrogen harvest index, and grain protein yield were recorded in 2014 along with NS4 treatment. The density of 33.3 plants per sq m and NS of 1 3 base + 1 3 tillering + 1 3 panicle formation are suggested for rice re-cropping.

Diurnal variation in methane emission from a rice paddy due to ebullition.

Diurnal fluctuations in methane (CH4 ) emission are frequently observed in rice paddy fields, yet the driving mechanisms behind these variations are not fully understood. We posited that the observed diurnal patterns are predominantly due to temperature-dependent bubbling emissions (ebullition). To investigate this hypothesis, we conducted measurements of CH4 emission in a Japanese rice paddy using static chambers coupled with a high-time-resolution CH4 analyzer that allowed us to partition the total flux into its two principal components: plant-mediated transport and ebullition. Diurnal variation in the total flux was minimal during the early parts of reproductive growth (panicle formation and booting stages), when plant-mediated emission was dominant. At a later stage (heading period), ebullition accounted for 43%-70% of the total emission, and CH4 emission via both pathways varied diurnally; however, the diurnal range was much greater for bubbling emission (ratio of maximum to minimum=3.5) than for plant-mediated emission (ratio of maximum to minimum=1.4). The magnitude of emissions due to ebullition depended on the temperature, but was greater during the flux-increasing phase in the morning than the flux-decreasing phase in the afternoon even at the same temperature, forming a hysteresis in the flux versus temperature relationship. These findings support our hypothesis and indicate that abiotic processes, such as a change in the solubility of gases and the temperature dependence of the gas-phase volume (Charles's law), may play a central role in shaping the diurnal pattern of the CH4 ebullition.

Introduction and adaptation of quinoa (<i>Chenopodium quinoa</i> Willd.) cultivars in Krasnodar region of Russia

Quinoa (Chenopodium quinoa Willd.) is a cultivated plant of the Amaranthaceae family of Peruvian origin with high nutritional value. The Krasnodar region of Russia is a region with favorable climatic conditions for growing quinoa. The studies were carried out on the basis of Quinoa Center LLC, located in the Novokubansky district of the Krasnodar Territory. Four quinoa varieties were used as research material: Blanca de Juli, White Peru, Salcedo, the local variety Seva (included in the State Register of the Russian Federation in 2017) served as the standard. Various morphological parameters of plants were assessed and phenological observations were carried out.The results showed statistically significant differences between varieties in plant productivity. The White Peru variety responded positively to the new conditions and was introduced without irrigation. The productivity of the panicle was on average 100 g, for the standard variety Seva - 70 g. In the dynamics of the ontogenetic development cycle of four quinoa varieties, it was established that the optimal sowing time in the conditions of the Krasnodar Territory is May. The tested varieties were also assessed for grain quality. In the conditions of the Krasnodar region they showed good results, thanks to selection for white grain and panicle uniformity. However, not all of them can be adapted, since they need constant watering and for late-ripening varieties autumn rains negatively affect their yield. The local early ripening variety Seva is of interest to Peru. In Peru, the main problem reducing production is low yield caused by frost in the Puno Peru region. The Seva variety reaches phenological phases: the beginning of panicle formation (R6), panicle formation (R7), flowering (R8) and full panicle ripening, physiological maturity (R12) and due to its early ripening it avoids frost. Therefore, the Seva variety can be recommended for sowing in the Puno-Peru region, since it has a gene pool that provides cold resistance but this requires detailed study. In general, to optimize the introduction of quinoa in Russia further research on adaptability in the Krasnodar region is necessary.

Factores ecológicos asociados a la fertilización nitrogenada en los arrozales y su influencia en la producción

This paper compares the effect of the time and form of nitrogen application upon rice yield. A discussion about the influence of the physical and Chemical characteristics of the water on denitrification and ammonia volatilization is included.
 The highest yield was obtained when fertilization was coincident with the tillering and panicle diferentiation, lower when it was coincident with the sown and panicle diferentiation, and lowest in the control without fertilization.
 Inorganic nitrogen concentrations in the water were high if the fertilization was coincident with the sown and tillering while it was low at the panicle formation, similar to that recorded in unfcrtilized plots.
 It was concluded that the lower production in the sown fertilization was due to high nitrogen losses favoured by high water temperatures and inorganic nitrogen concentrations.

TFIIB-Related Protein BRP5/PTF2 Is Required for Both Male and Female Gametogenesis and for Grain Formation in Rice.

Transcription factor IIB (TFIIB) is a general transcription factor for RNA polymerase II, exerting its influence across various biological contexts. In the majority of eukaryotes, TFIIB typically has two homologs, serving as general transcription factors for RNA polymerase I and III. In plants, however, the TFIIB-related protein family has expanded greatly, with 14 and 9 members in Arabidopsis and rice, respectively. BRP5/pollen-expressed transcription factor 2 (PTF2) proteins belong to a subfamily of TFIIB-related proteins found only in plants and algae. The prior analysis of an Arabidopsis atbrp5 mutant, characterized by a T-DNA insertion at the 5' untranslated region, demonstrated the essential role of BRP5/PTF2 during the process of pollen germination and embryogenesis in Arabidopsis. Using a rice transformation system based on CRISPR/Cas9 technology, we have generated transgenic rice plants containing loss-of-function frameshift mutations in the BRP5/PTF2 gene. Unlike in the Arabidopsis atbrp5 mutant, the brp5/ptf2 frameshift mutations were not transmitted to progeny in rice, indicating an essential role of BRP5/PTF2 in both male and female gamete development or viability. The silencing of rice BRP5/PTF2 expression through RNA interference (RNAi) had little effect on vegetative growth and panicle formation but strongly affected pollen development and grain formation. Genetic analysis revealed that strong RNAi silencing of rice BRP5/PTF2 was still transmissible to progeny almost exclusively through female gametes, as found in the Arabidopsis atbrp5 knockdown mutant. Thus, reduced rice BRP5/PTF2 expression impacted pollen preferentially by interfering with male gamete development or viability. Drawing upon these findings, we posit that BRP5/PTF2 assumes a distinct and imperative function in the realm of plant sexual reproduction.

A Labor-Saving Fertilization Method Omitting Top Dressing at the Panicle Formation Stage Utilizing Controlled Release Fertilizer in Two-Rowed Barley for Food

A Labor-Saving Fertilization Method Omitting Top Dressing at the Panicle Formation Stage Utilizing Controlled Release Fertilizer in Two-Rowed Barley for Food

Nitrogen uptake pattern of dry direct-seeded rice and its contribution to yields in northeastern Japan

ABSTRACT Dry direct-seeded rice (DDSR) cultivation is expected to reduce production costs compared with transplanted rice (TPR); however, its low N use efficiency (NUE) has hindered cost reduction. We conducted DDSR field experiments for 3 years using a standard cultivar (‘Akitakomachi’) and a high-yielding cultivar (‘Yumiazusa’) grown with a single application of coated urea (CU) or split applications of normal urea (NU) to determine factors limiting yield and NUE and compared growth and yields of TPR grown in adjacent fields. DDSR yield was lower than that of TPR at comparable N levels by 11% due to low fertilizer recovery rate, crop NUE (CNUE, yield per unit N uptake), and poor grain filling by meteorological factors. Crop N uptake at maturity in DDSR was similar to or even greater than that in TPR, but poor vegetative growth in DDSR and low crop N uptake until panicle formation (PF) resulted in limited spikelet density and CNUE compared with TPR. Analysis of the N uptake pattern suggests that enhancing early leaf development can improve N uptake until PF and thus CNUE in DDSR. NU yielded as much as CU, so it can potentially reduce the cost of production because of its lower price, but the optimal N proportion and application stage in the split application needs scrutinizing. ‘Yumiazusa’ had better initial growth, CNUE, and yield than ‘Akitakomachi’ in DDSR. To leverage these traits for further yield improvements, we also need to consider suitable phenological characteristics to ensure favorable climatic conditions during the grain-filling period.

Light intensity-mediated auxin homeostasis in spikelets links carbohydrate metabolism enzymes with grain filling rate in rice.

Low light (LL) stress during the grain-filling stage acutely impairs the quality and quantity of starch accumulation in rice grains. Here, we observed that LL-induced poor starch biosynthesis is modulated by auxin homeostasis, which regulates the activities of major carbohydrate metabolism enzymes such as starch synthase (SS) and ADP-glucose pyrophosphorylase (AGPase) in rice. Further, during the grain-filling period under LL, the starch/sucrose ratio increased in leaves but significantly decreased in the developing spikelets. This suggests poor sucrose biosynthesis in leaves and starch in the grains of the rice under LL. A lower grain starch was found to be correlated with the depleted AGPase and SS activities in the developing rice grains under LL. Further, under LL, the endogenous auxin (IAA) level in the spikelets was found to be synchronized with the expression of a heteromeric G protein gene, RGB1. Interestingly, under LL, the expression of OsYUC11 was significantly downregulated, which subsequently resulted in reduced IAA in the developing rice spikelets, followed by poor activation of grain-filling enzymes. This resulted in lowered grain starch accumulation, grain weight, panicle number, spikelet fertility, and eventually grain yield, which was notably higher in the LL-susceptible (GR4, IR8) than in the LL-tolerant (Purnendu, Swarnaprabha) rice genotypes. Therefore, we hypothesize that depletion in auxin biosynthesis under LL stress is associated with the downregulation of RBG1, which discourages the expression and activities of grain-filling enzymes, resulting in lower starch production, panicle formation, and grain yield in rice.

Energy and Biomass Yield of Industrial Hemp (Cannabis sativa L.) as Influenced by Seeding Rate and Harvest Time in Polish Agro-Climatic Conditions

ABSTRACT Energy produced directly from biomass represents an important part of available alternative energy sources. Industrial hemp has potential energy yields that are higher than those of many other energy crops and, as an annual herbaceous crop, hemp fits into existing crop rotations. The total biomass of hemp per hectare is similar to other energy crops, including mostly grown giant miscanthus, poplar, or willow. Industrial hemp is characterized by a short growing cycle, a decreased need for pesticides, and low plant maintenance. The energetic value of hemp depending on agrotechnical factors, such as sowing density and time of harvest, has been assessed in this study. A three-year field experiment was carried out to prove the possibility of using whole plants and separately hemp straw and panicles for energy purposes. C. sativa was sown at eight sowing rates − 5, 10, 15, 20, 30, 40, 50, and 60 kg · ha−1 and harvested at three developmental stages: at the beginning of panicle formation, at full flowering and at the end of seed setting. The optimal harvest time of hemp grown for energetic purposes was demonstrated to be at full flowering and the optimal sowing rate at 30 kg · ha−1 when hemp yielded 14.65 t · ha−1 equals 275.56 GJ · ha−1.

The Integration of Genome-Wide Association Study and Homology Analysis to Explore the Genomic Regions and Candidate Genes for Panicle-Related Traits in Foxtail Millet

Panicle traits are important factors affecting yield, and their improvement has long been a critical goal in foxtail millet breeding. In order to understand the genetic basis of panicle formation, a large-scale genome-wide association study (GWAS) was performed in this study for six panicle-related traits based on 706,646 high-polymorphism SNP loci in 407 accessions. As a result, 87 quantitative trait loci (QTL) regions with a physical distance of less than 100 kb were detected to be associated with these traits in three environments. Among them, 27 core regions were stably detected in at least two environments. Based on rice-foxtail millet homologous comparison, expression, and haplotype analysis, 27 high-confidence candidate genes in the QTL regions, such as Si3g11200 (OsDER1), Si1g27910 (OsMADS6), Si7g27560 (GS5), etc., affected panicle-related traits by involving multiple plant growth regulator pathways, a photoperiod response, as well as panicle and grain development. Most of these genes showed multiple effects on different panicle-related traits, such as Si3g11200 affecting all six traits. In summary, this study clarified a strategy based on the integration of GWAS, a homologous comparison, and haplotype analysis to discover the genomic regions and candidate genes for important traits in foxtail millet. The detected QTL regions and candidate genes could be further used for gene clone and marker-assisted selection in foxtail millet breeding.

Kitagenki, a high-yielding rice variety, exhibits a high yield potential under optimum crop management practices

In the Hokkaido region of Japan, a new japonica-type high-yielding rice variety (HYV), Kitagenki, demonstrated higher grain yield than the early developed japonica-type HYVs; however, its yield potential is unknown. Therefore, a four-year (2015–2018) field study was conducted to elucidate the (1) yield potential of Kitagenki, (2) effect of early and late nitrogen (N) applications on the grain yield of Kitagenki, and (3) effect of early N application and planting density on the grain yield of Kitagenki. Experiment 1 consisted of three early N (10.5 N: basal 10.5 g N m−2, 16.5 N: basal 16.5 g N m−2, and 10.5 N + T1: basal 10.5 g N m−2 with topdressing of 6 g N m−2 at the panicle formation stage) combined with two late N (− T2: no topdressing at the full-heading stage, and + T2: topdressing of 6 g N m−2 at the full-heading stage) applications. Experiment 2 consisted of two early N (10.5 N and 16.5 N) applications combined with two planting densities (standard planting: 22.8–23.0 hill m−2 and sparse planting: 11.4–11.5 hill m−2). The yield potential of Kitagenki was approximately 1200 g m−2 of gross hulled grain, which is the highest yield recorded among japonica-type HYVs cultivated in Japan. In experiment 1, the grain yield of Kitagenki was improved by both early N (16.5 N, 10.5 N + T1 > 10.5 N) and late N (+ T2 > − T2) applications owing to the improved sink capacity and source ability. We suggest 10.5 N + T1 + T2 and 16.5 N + T2 as the optimum combination of early and late N applications to stably maximize the grain yield of KG. In experiment 2, the grain yield of KG was significantly improved by early N (16.5 N > 10.5 N) application but not significantly by planting density. In 16.5 N, sparse planting tended to produce a higher grain yield by lowering the lodging scores and increasing the source-sink ratio compared to those obtained with standard planting. Therefore, we suggest 16.5 N sparse planting as the optimum combination of early N application and planting density to stably maximize the grain yield of Kitagenki.

Cultivation of sorts and hybrids of sweet corn as the main crop in Karakalpakstan

The aim of the study was to determine the growth, development and yield of sweet corn varieties and hybrids as vegetables during the soil-climatic conditions of Karakalpakstan.Methods. The 8 cultivars and 8 hybrids studied were evaluated for growth, development and yield in Karakalpakstan in 2017-2019. Selection work was carried out on varieties and hybrids. Varieties and hybrids with a positive result based on the selection results were recommended for use in subsequent experiments.Results. After sowing the seeds of the studied 8 varieties and 8 hybrids of vegetable (sweet) corn, the duration of the germination period was 7-9 days. Relatively early germination between cultivars and hybrids Zamin, Can. Pedro 2 Inta, Berys varieties, relatively late germination was recorded in 9 days in SPV 1022, Leonard's Early, Honey Bontam F1, Spirit F1, Megaton F1, Baron F1, Soyan F1, Hybrid F1. It has been established that the period from germination to the stage of leaf formation (7 leaves) is 13-16 days, the period from the stage of leaf formation (7 leaves)to the panicle formation is 23-33 days, the period from the panicle formation to flowering is 4-6 days, the period from flowering to the cob formation is 9-15 days. In the studied varieties and hybrids, the period from the cob formation to milky ripeness was 13-18 days, from milky ripeness to waxy ripeness lasted up to 4-8 days.The study of the duration of the development phases of varieties and hybrids showed that the growth period from germination to milky-wax ripeness is 75-85 days. Early yield was observed in hybrids Baron F1, Sweet star F1, Spirit F1, Soyan F1, vegetation period 73-77 days, relatively early yield was observed in varieties and hybrids Zamin, Sentinel F1, SPV 1022, Osnova 209, Hybrid F1, Can Pedro 2 Inta, Clx3349ys clause, growing season 79-81 days.The selection of varieties and hybrids most appropriate to the soil and climatic conditions of Karakalpakstan was carried out and recommended for cultivation by farmers and dekhkan farms.

A stepwise route to domesticate rice by controlling seed shattering and panicle shape

Asian rice (Oryza sativa L.) is consumed by more than half of the world's population. Despite its global importance, the process of early rice domestication remains unclear. During domestication, wild rice (Oryza rufipogon Griff.) acquired non-seed-shattering behavior, allowing humans to increase grain yield. Previous studies argued that a reduction in seed shattering triggered by the sh4 mutation led to increased yield during rice domestication, but our experiments using wild introgression lines show that the domesticated sh4 allele alone is insufficient for shattering loss in O. rufipogon. The interruption of abscission layer formation requires both sh4 and qSH3 mutations, demonstrating that the selection of shattering loss in wild rice was not as simple as previously suggested. Here we identified a causal single-nucleotide polymorphism at qSH3 within the seed-shattering gene OsSh1, which is conserved in indica and japonica subspecies but absent in the circum-aus group of rice. Through harvest experiments, we further demonstrated that seed shattering alone did not significantly impact yield; rather, yield increases were observed with closed panicle formation controlled by SPR3 and further augmented by nonshattering, conferred by integration of sh4 and qSH3 alleles. Complementary manipulation of panicle shape and seed shattering results in a mechanically stable panicle structure. We propose a stepwise route for the earliest phase of rice domestication, wherein selection of visible SPR3-controlled closed panicle morphology was instrumental in the sequential recruitment of sh4 and qSH3, which together led to the loss of shattering.

Fixing critical limits of boron in rice soils of Karaikal region, Puducherry union territory, India

Boron is relatively immobile in plants and its deficiency can cause serious yield reduction in rice by retarding panicle formation. Karaiakal region of Puduchuerry union terittory includes different soils with varying fertility status thus supplying boron at optimum level is a must concern to enhance the rice productivity.A pot experiment was conducted to fix critical limits of boron in soils and rice of this Karaikal region. Forty surface soil samples (0-15 cm) were collected from Inceptisol, Entisol and Vertisol soil orders of different locations in Karaikal region. The experiment was conducted with three levels of boron viz., 0, 1 and 2 ppm applied through borax in a factorial completely randomized design with three replications. The available B content of soil was estimated with five extractants. The critical limits of hot water, hot 0.01 M CaCl2, 0.05 M HCl, 1.0 M NH4OAc, 0.01M CaCl2+ 0.05 M Mannitol extractable B were found to be 0.50, 0.58, 0.46, 0.45 and 0.39 ppm in Inceptisol, 0.48, 0.59, 0.44, 0.39 and 0.48 ppm in Entisol and 0.45, 0.54, 0.45, 0.44 and 0.41ppm in Vertisol and a critical limit of 31.0, 39.0 and 34.0 ppm B in rice plant for Inceptisol(0.5ppm), Entisol(0.48 ppm) and Vertisol(0.45 ppm) as determined by Cate and Nelson’s graphical procedure. Among the extractants the hot water extractant showed the highest significant and positive correlation with Bray’s percent yield(0.48,0.47and 0.48), plant B content(0.041*, 0.019* and 0.271*) and B uptake(0.012*, 0.646* and 0.293*), respectively in Inceptisol, Entisol and Vertisol. From this study, the indicating knowledge of critical limit of boron will help to avoid yield loss of rice in the study region.

ABERRANT PANICLE ORGANIZATION2 controls multiple steps in panicle formation through common direct-target genes.

At the transition from vegetative to reproductive growth in rice (Oryza sativa), a developmental program change occurs, resulting in panicle (rice inflorescence) formation. The initial event of the transition is the change of the shoot apical meristem to an inflorescence meristem (IM), accompanied by a rapid increase in the meristem size. Suppression of leaf growth also occurs, resulting in the formation of bracts. The IM generates branch meristems (BMs), indeterminate meristems that reiteratively generate next-order meristems. All meristems eventually acquire a determinate spikelet meristem identity and terminate after producing a floret. ABERRANT PANICLE ORGANIZATION2 (APO2) is the rice ortholog of Arabidopsis (Arabidopsis thaliana) LEAFY (LFY), a plant-specific transcription factor (TF). APO2 is a positive regulator of panicle branch formation. Here, we show that APO2 is also required to increase the meristem size of the IM and suppress bract outgrowth. We identified genes directly and indirectly regulated by APO2 and identified APO2-binding sites. These analyses showed that APO2 directly controls known regulators of panicle development, including SQUAMOSA PROMOTER BINDING PROTEIN LIKE14 and NECK LEAF1. Furthermore, we revealed that a set of genes act as downstream regulators of APO2 in controlling meristem cell proliferation during reproductive transition, bract suppression, and panicle branch formation. Our findings indicate that APO2 acts as a master regulator of rice panicle development by regulating multiple steps in the reproductive transition through directly controlling a set of genes.