Efficiency Of Seed Production Research Articles

Principal component analysis of morpho-floral traits in Oryza sativa × Oryza longistaminata advanced backcross lines of rice

Hybrid rice technology substantially improves the food security of South Asian countries where rice (Oryza sativa L.) is a staple food. Several traits contribute to hybrid seed production efficiency, among which stigma exsertion is crucial for enhancing production by facilitating out-crossing pollination. This study evaluated the variation patterns and relative impact of 12 morpho-floral traits on overall variability in advanced backcross lines derived from crosses CRMS 32B cv. Oryza sativa and Oryza longistaminata. For this study, 290 BC4F2 lines were grown during Kharif 2019 in 3 replications using a randomized complete block design (RCBD). Principle component analysis (PCA) was performed on all traits, and the findings revealed 11 principal components (PCs). Out of 11 PCs, the first five displayed eigenvalues exceeding 1, collectively explaining 78.78% of the total variability. PC1, PC2, PC3, PC4, and PC5 contributed 26.36%, 19.94%, 14.22%, 9.81%, and 8.44% of the variation, with eigenvalues of 3.16, 2.39, 1.71, 1.18 and 1.01, respectively. PC1 was predominantly associated with yield-related traits such as panicle length, plant height, grain yield per plant, grains per panicle, and effective tillers per plant. On the other hand, PC2 was mainly associated with outcrossing-related floral traits such as total stigma exsertion percentage, dual stigma exsertion percentage, and single stigma exsertion percentage. However, PC3 and PC4 were associated with both floral and yield-related traits, i.e., days to 50% flowering (DF), days to maturity (DM), plant height (PH), effective tillers per plant (ETPP), spikelet fertility percentage (SFP), grain yield per plant (GYPP) and grains per panicle (GPP). Therefore, PC1, PC2, PC3, and PC4 were major contributors to rice hybrid seed production.

Effects of dietary supplementation with benthic diatom Amphora coffeaeformis on blood biochemistry, steroid hormone levels and seed production efficiency of Nile tilapia Oreochromis niloticus broodstock.

Aquafeed additive quality and quantity remain pivotal factors that constrain the sustainability and progress of aquaculture feed development. This study investigates the impact of incorporating the benthic diatom Amphora coffeaeformis into the diet of Nile tilapia (Oreochromis niloticus) broodstock, on the blood biochemistry, steroid hormone (SH) levels and seed production efficiency. Broodstock females displaying mature ovary indications were initially combined with males at a ratio of three females to one male. A total of 384 adult Nile tilapia (288 females and 96 males) were used, with 32 fish (24 females and eight males) assigned to each of 12 concrete tanks (8 m³; 2 m × 4 m × 1 m), with three replicate tanks for each dietary treatment, throughout a 14-day spawning cycle until egg harvest. Fish were fed one of four different dietary treatments: AM0% (control diet), and AM2%, AM4% and AM6% enriched with the diatom A. coffeaeformis at levels of 20, 40 and 60 g/kg of diet respectively. At the trial's conclusion, total protein, albumin, triglyceride and creatinine), SHs (follicle-stimulating hormone, luteinizing hormone, free testosterone, total testosterone, progesterone and prolactin) and seeds production efficiency of Nile tilapia improved significantly (p < 0.05) in alignment with the increment of A. coffeaeformis supplementation. The findings propose that including A. coffeaeformis at levels ranging from 4% to 6% could be effectively employed as a feed additive during the Nile tilapia broodstock's spawning season.

Transcriptome disclosure of hormones inducing stigma exsertion in Nicotiana tabacum by corolla shortening

BackgroundStigma exsertion is an essential agricultural trait that can promote cross-pollination to improve hybrid seed production efficiency. However, the molecular mechanism controlling stigma exsertion remains unknown.ResultsIn this study, the Nicotiana tabacum cv. K326 and its two homonuclear-heteroplasmic lines, MSK326 (male-sterile) and MSK326SE (male-sterile and stigma exserted), were used to investigate the mechanism of tobacco stigma exsertion. A comparison of the flowers between the three lines showed that the stigma exsertion of MSK326SE was mainly due to corolla shortening. Therefore, the corollas of the three lines were sampled and presented for RNA-seq analysis, which found 338 candidate genes that may cause corolla shortening. These genes were equally expressed in K326 and MSK326, but differentially expressed in MSK326SE. Among these 338 genes, 15 were involved in hormone synthesis or signal transduction pathways. Consistently, the content of auxin, dihydrozeatin, gibberellin, and jasmonic acid was significantly decreased in the MSK326SE corolla, whereas abscisic acid levels were significantly increased. Additionally, seven genes involved in cell division, cell cycle, or cell expansion were identified. Protein-protein interaction network analysis identified 45 nodes and 79 protein interactions, and the largest module contained 20 nodes and 52 protein interactions, mainly involved in the hormone signal transduction and pathogen defensive pathways. Furthermore, a putative hub gene coding a serine/threonine-protein kinase was identified for the network.ConclusionsOur results suggest that hormones may play a key role in regulating tobacco stigma exsertion induced by corolla shortening.

Effects of Rhizobium Strains on Seed Yield and Yield Related Traits of Chickpea (Cicer aritienum L.) Varieties at Ambo, Ethiopia

The chickpea (Cicer arietinum L.) is a significant legume food crop in West Showa that farmers exploit to generate revenue and sustenance. Nevertheless, two major obstacles to production are the scarcity of high-quality seed and the poor fertility of the soil. Thus, the purpose of this study was to evaluate how Rhizobium inoculation affected yield, growth, and its constituent parts. Four Rhizobium strains (Cp11, Cp17, Cp41, and control) x four varieties (Eshete, Dimtu, Teketay, and Local) organized in factorial combinations were assessed using a randomized complete block design with three replications. All phenology and growth parameters, yield components, seed yield, and productivity indices were significantly influenced by both variety and Rhizobium strain, with the exception of crop phenology and hundred seed weight, which were not significantly influenced by Rhizobium strain. Plant height and the number of pods per plant were significantly impacted by the interaction between the R strain and variety. Four types yielded seed with a range of 2013.89 to 2777.78 kg ha-1, whereas inoculation procedures produced seed with a range of 2152.78 to 2690.97 kg ha-1. The Teketay variety and seeds infected with the Cp17 Rhizobium strain produced the best seed yield. Higher grain yield index per day, Rhizobium sensitive or infection index, yield index, and seed production efficiency were also seen in Teketay variety and seeds infected with Cp17 Rhizobium strain. The largest seed yield was produced by the Teketay variety inoculated with the Cp17 Rhizobium strain, and in most cases, the enhanced varieties' seeds inoculated with the Cp17 strain also produced high yields.

Increasing the seed production efficiency of autumn potato with plant growth regulators

AbstractHigher productivity of seed‐size tubers is a significant issue in seed potato (Solanum tuberosum) production systems. Punjab, in northwest India, is the hub of seed potato production and supplies 60% seed requirement of the country. However, to improve the productivity of seed‐size (3.5–4.5 cm) tubers, research trials were run at Ludhiana for 2 years (autumn 2019 and 2020) to examine the effectiveness of plant growth regulators in enhancing the growth and yield of seed potatoes. The experimental trial with 11 growth regulation treatments—control (water spray), IBA (indole‐3‐butyric acid) (100 mg/L), IBA (200 mg/L), NAA (1‐naphthaleneacetic acid) (25 mg/L), NAA (50 mg/L), ethrel (25 mg/L), ethrel (50 mg/L), GA3 (gibberellic acid) (100 mg/L), GA3 (200 mg/L), jeevamrit, and waste decomposer—was laid out in a randomized complete block design with three replications. GA3 (200 mg/L) applied at 45 and 60 days after sowing, resulted in significantly higher seed and total tuber yields than all other growth regulation treatments. It produced 34.9% and 31.5% higher total tuber yields as compared to the untreated control. However, it had no significant impact on undersized and small‐sized tuber yield and number. GA3 at a concentration of 200 mg/L yielded the highest seed production efficiency of 51.7% and 38.9% compared to the control. This underscores the significance of precise application concentrations in controlling both seed yield and size.

Comparative evaluation of early potato varieties and the mid-season variety Zlatka and ways to improve their seed production efficiency in the forest-steppe of Priobye

The paper provides data on the comparative assessment of early potato varieties on two main soil types in the forest-steppe of Priobye. The experiments were conducted from 2020 to 2022 in the Novosibirsk District of the Novosibirsk Region on leached chernozem soil at the "Praktik" Experimental Farm (a division of Novosibirsk SAU) and on grey forest heavy loamy soil at CJSC agricultural enterprise "Michurinets." The research aimed to study the efficiency of using the modern gene pool of early potato varieties and to explore ways to improve their virus-free seed production. The study achieved high potato variety yields in conditions of leached chernozem soil ("Praktik") and grey forest heavy loamy soil (CJSC agricultural enterprise "Michurinets") located in the northern forest-steppe of the Novosibirsk Priobye. Leached chernozem on experimental plots had a humus content of 6.76%, gross nitrogen of 0.24%, phosphorus of 0.21%, and potassium 1.25%. The concentration of quickly hydrolysable nitrogen was 12.3, mobile phosphorus was 25.2, and exchangeable potassium was 12 mg/100 g of soil, with a pH of 5.89. Grey forest soil contained 3.8% humus with a pH of 5.53; Nitrate nitrogen of about 10 mg/kg; mobile phosphorus of 12.8 mg/100 g; Exchangeable potassium of 9.2 mg/100 g of soil. The research showed that on grey forest soil in open ground conditions, the productivity of early potato varieties was as follows: Red Scarlett - about 32 t/ha, Rozara - 30 t/ha, and the mid-season variety Zlatka - 28 t/ha. It was demonstrated that the seed fraction in the yield dominated these varieties. The authors noted a coefficient of variation of the fractional composition at the level of V=12.6-28%, depending on the array. The highest yield of virus-free tubers was observed in the Terra and Santé varieties. On leached chernozem soil during the study of early types, the minimum productivity was 1024 g/plant for the Rozara variety, 987 g/plant for the Riviera variety, and 986 g/plant for the Kolomba variety, which is significantly higher than the standard (Lyubava variety). It was statistically determined that the yield of early potatoes depended on genotype by 37% and on the year's conditions by 27%.

Near-Infrared Spectral Analysis for Assessing Germination Rate of Rapeseed Seeds: An Applied Sciences Approach

Brassica rapa, commonly known as the rapeseed plant, is globally recognized for its nutrient-rich composition and oil-packed seeds, earning its distinction as a substantial oil-seed crop. The seed quality, particularly the germination rate, is instrumental in guaranteeing a high-yield rapeseed crop. Given this, the accurate, quantitative determination and selection of germination rates in seed batches prior to sowing is of paramount importance. However, conventional germination tests, employed to determine the average germination rate of seed batches, are marred by substantial time and cost inefficiencies. This study proposes the use of near-infrared spectral analysis as a proficient, non-invasive approach for assessing germination rates in rapeseed seed batches. The research involved artificial aging of seeds procured from a variety of rapeseed strains, resulting in 228 batches with a broad germination rate spectrum of 15.73% to 99.13%. We recorded near-infrared diffuse reflectance spectra and applied a range of strategies for spectral data preprocessing and feature variable selection. Furthermore, we leveraged support vector regression (SVR) modeling to augment the detection methodology. SVR training and detection were conducted using MATLAB, with selected feature wavelengths undergoing rigorous scrutiny and discussion. The results indicated that employing Savitzky–Golay convolution smoothing for spectral preprocessing, along with Synergy interval Partial Least Squares (SiPLS) in conjunction with Random Frog (RF) for the selection of 50 feature wavelength points, yielded optimal germination rate prediction performance within the SVR model. The coefficients of determination (R2c) for the training set and (R2p) for the testing set were observed to be 0.8559 and 0.8386, respectively, while the Root Mean Square Errors of Calibration (RMSEC) and Prediction (RMSEP) were calculated to be 13.76% and 17.04%. The mechanism of detecting seed vigor through near-infrared spectroscopy was analyzed based on joint variable screening and sensitive variable traceability. Consequently, the SG–SiPLS–RF–SVR model demonstrates its effectiveness in predicting the average germination rate of seed batches, offering a rapid, non-invasive detection method that can be universally applied to various rapeseed strains, thus significantly improving seed production efficiency.

Identifying successful combinations by fertility index in old garden roses and hybrid tea roses crosses.

The success of rose breeding programs is low due to poor seed sets and germination rates. Determining fertile parents and cross combinations that show high compatibility could increase the effectiveness of breeding programs. In this study, three rose varieties belonging to Rosa × hybrida (Jumilia, First Red and Magnum), and two old garden rose species (Black Rose and Cabbage Rose) with known ploidy levels were reciprocally crossbred under controlled conditions to determine the successful crosses by checking fertility. The pollen germination rate (PG), crossability rate (CR), seed number per fruit (SNpF), seed production efficiency (SPE), seed germination rate (SGR), fruit weight (FW), seed weight (SW) and stigma number (SiN), etc. were recorded. Comprehensive fertility index value was calculated. Principal component analysis (PCA), correlation matrix, and hierarchical heat map were used to evaluate the data. The findings showed that old garden roses had more viable pollen than hybrid tea roses. The crossing success improved as pollen fertility increased. Also, female parent fertility improved crossing success just as much as pollen fertility. Although the pollen fertility and stigma numbers were low, some combinations had higher CR and SPE. The maximum SPE (from 8.67% to 19.46%) was determined in combinations where Black Rose was the female parent despite the lower stigma number and low pollen fertility. The highest CR was recorded in Black Rose × First Red (94.36%). All combinations in which Black Rose was used as the female parent had a more stable CR. The SNpF of combinations where hybrid rose varieties were female parents and old garden roses were pollen parents was higher than other combinations where hybrid rose varieties were both female and pollen parents. The SPE in intraspecific crosses was lower than that obtained from interspecific crosses. Moreover, the SGR decreased in combinations that produced heavier seeds. The results suggested that SPE is a more accurate parameter than SNpF in demonstrating combination success in breeding programs. Black Rose × First Red, Black Rose × Jumilia, Black Rose × Magnum and Black Rose × Cabbage Rose combinations can be used successfully as the PCA and heat map showed. Black Rose showed better performance as both seed and pollen parents according to the comprehensive fertility index. From the correlation matrix, it is understood that the number of stigmas cannot be an important criterion in parent selection. Old garden roses can be used as parents to increase the success of breeding programs. However, it is necessary to reveal how successful they are in transferring desired characteristics such as scent, petal number, and color.

Fruit characterization and plant quality of Spanish cedar (Cedrela odorata L.) during the early nursery stage

Objective: The aim of this study was to characterize Spanish cedar (Cedrela odorata L.) fruits and seeds, and to evaluate the effects of provenance, substrata, and fertilizer on germination and plant quality in nursery. Design/Methodology/Approach: The fruits and seeds from Spanish cedars were collected in three different towns: C-32 (Francisco Trujillo Gurria), C-40 (Ernesto Aguirre Colorado), and C-41 (Carlos A. Madrazo). Those towns are in Plan Chontalpa, Tabasco, Mexico. After they were harvested, the samples were morphometrically characterized. Seed production efficiency (SPE), germination (%), and Dickson Quality Index (DQI) were estimated. Two completely randomized experimental designs with factorial arrangement of treatments were used. The factors were the provenance, four or three substrata, and two levels of Greenfool® 600 fertilizer. Results: Fruits of 3.46 cm in length and 1.81 cm in width were collected; the mean number of seeds per fruit was 49.36. Seed production efficiency ranged from 48.1% to 52.72%, with 32.86% germination. The seeds from Town C-41 obtained the highest germination percentage, with the use of black soil:sand as substrate. The plants fertilized and developed in black soil:sand substrate obtained a higher DQI. Study Limitations/Implications: The activity restriction caused by the Sars-Cov-2 pandemic was the main limitation. The lower number of producers and plantations from Town C-32 was the implication. Findings/Conclusions: Fruit and seed characteristics were different among provenances. The provenance impacted on seed germination, but not on the plant quality index (DQI). Instead, the substrate and fertilizer impacted on the DQI.

Assessment of time of harvest at different moisture contents on seed yield attributes of ten pigeon pea (Cajanus cajan) genotypes

Grain moisture content is a key indicator of an appropriate harvest period of seeds on the field and could also be used to effectively stabilize cereal products especially when physical attributes is to be evaluated. This study evaluated effect of time of harvest at different moisture contents on seed yield attributes of ten pigeon pea genotypes. The ten pigeon pea genotypes used for the experiment were sourced from International Institute of Tropical Agriculture (IITA) Ibadan, Oyo State, Nigeria. The field experiment was a Randomized Completely Block Design (RCBD) with three replications. The seeds were harvested at maturity on the field at 12, 15 and 17 % moisture content. At each harvested moisture content, the following seed yield parameters were evaluated periodically on five observational plants from each net plot-; number of pods per plant, number of seeds/pod, seed yield/plant, pod weight /plant, 100 seed weight/plot and seed production efficiency. Data collected were subjected to analysis of variance and Principal component analysis was used to identify characters that contributed majorly to variation within the genotypes under each treatment. The result showed that NSWCC-18b, NSWCC-19 and NSWCC-18 had an outstanding performance in the entire seed- yield attributes, evaluated for various moisture contents and could therefore, be used as dependable genotypes in pigeon pea seed development programme. It is thereby, recommended that, pigeon pea seeds should be harvested at 15% moisture content for effective maintenance of quality, quantity and vigor.

Morphological and physiological mechanism of cytoplasmic inheritance stigma exsertion trait expression in tobacco (Nicotiana tabacum)

Stigma exsertion is an essential outcrossing trait that can improve hybrid seed production efficiencies. In this study, the morphological and physiological mechanisms of cytoplasmic inheritance stigma exsertion trait expression in a tobacco line (MSK326SE) which generated from a stigma exsertion tobacco mutant through continuous backcross were investigated. Compared with its homonuclear-heteroplasmic lines (MSK326 and K326 with inserted stigmas), the exserted stigma phenotype of MSK326SE was mainly caused by corolla shortening, while was stable under different environmental temperature. The different responses of mainly endogenous hormones and expression of cell division- and expansion-related genes caused the differences in cell division and expansion in different flower organs, which further determined the lengths of the corolla. Furthermore, the significant decrease of MSK326SE corolla epidermal cell size caused corolla shortening and finally resulting in stigma exsertion. Exogenous JA could shorten the corolla and more effective increased stigma exsertion degree of MSK326SE, suggesting a potential relationship between stigma exsertion and high JA levels during early bud development. The hybrid seed production efficiency could be improved in tobacco. Our results provide a basis for elucidating the cytoplasmic inheritance stigma exsertion trait expression in tobacco while helping to improve hybrid seed production efficiency.

Optimum time for hand pollination in yam (Dioscorea spp.).

Hand pollination success rate is low in yam (Dioscorea spp.), due partly to suboptimal weather conditions. Thus, determining the most suitable time for pollination could improve the pollination success in yam breeding programs. We performed continuous hand pollination within flowering windows of D. rotundata and D. alata for two consecutive years to determine the most appropriate month, week, and hours of the day allowing maximum pollination success. In D. alata crossing block, we observed significant differences among crossing hours for pollination success (p = 0.003); morning hours (8–12 a.m.) being more conducive than afternoons (12–5 p.m.). No significant differences existed between crossing hours in D. rotundata, though the mid-day seemed optimal. For both species, the time interval 11–12 a.m. was more appropriate for crossing while 4–5 p.m. was the poorest. However, in vitro pollen germination tests showed that mid-day pollen collection (12 noon–2 p.m.) had better results than both extremes, though there were strong genotypic effects on outcomes. Pollination success rates differed significantly among months for D. alata (p < 0.001) but not for D. rotundata (p > 0.05). Differences in pollination success existed across weeks within flowering windows of both D. alata (p < 0.001) and D. rotundata (p = 0.004). The seed production efficiency (SPE) had a similar trend as the pollination success rate. No clear pattern existed between the pollination time and the seed setting rate (SSR) or seed viability (SV), though their dynamics varied with weeks and months. This study provided an insight on the dynamics of pollination outcomes under the influence of pollination times and allows detecting months, weeks, and hours of the day when hybridization activities should be focused for better results.

Strengths and weaknesses of organized crop seed production by smallholder farmers: A five-country case study

In many countries, smallholder farmers play a key role in food crop seed production. So far, the community roles, operational structures, seed production efficiency, aspects of sustainability, and the social and policy environments in which these groups operate have been poorly studied and described. The present study attempts to better understand these factors by drawing cases from twenty-five seed producer groups in five countries (Vietnam, Uganda, Zambia, Niger, and Guatemala) that deal with nine crops in total (rice, maize, sorghum, pearl millet, common bean, cowpea, soybean, groundnut, potato and sweet potato). Results of the study show all groups supply a significant share of seed offered in local markets. It appeared that all groups received major support for capacity development from a broad range of actors including local and national governments, public institutions, national seed companies and development organizations. Several groups operate under seasonal contracts with institutional seed buyers, whereas other groups sell most of their seed in local markets to fellow farmers. To support seed quality and render product branding meaningful, most groups have established subgroups for crop monitoring and seed inspection, and for gathering and using market intelligence. Some, but not all groups depend on formal seed certification. Two key challenges stand out across seed producer groups interviewed. First, most seed producer groups experience difficulties in accessing good-quality early generation seed (EGS) on time, like in the formal seed sector in many countries. Second, in most groups packaging and labelling of the seed produced and offered in local markets is suboptimal, hindering further professionalization. Moreover, groups invariably have a poor understanding of applicable seed policy and legislation. Our observations point at actions that external stakeholders could undertake to strengthen smallholder farmer seed production in recognition of their contribution to food and nutrition security.

Cross compatibility in intraspecific and interspecific hybridization in yam (Dioscorea spp.)

Yam (Dioscorea spp.) is a staple crop for millions of people in the tropics and subtropics. Its genetic improvement through breeding is being challenged by pre-zygotic and post-zygotic cross-compatibility barriers within and among species. Studies dissecting hybridization barriers on yam for improving the crossability rates are limited. This study aimed to assess the cross-compatibility, which yielded fruit set, viable seeds and progeny plants in an extensive intraspecific and interspecific crossing combinations in a yam genetic improvement effort to understand the internal and exogenous factors influencing pollination success. Cross-compatability was analyzed at the individual genotype or family level using historical data from crossing blocks and seedling nurseries from 2010 to 2020 at the International Institute of Tropical Agriculture (IITA). The average crossability rate (ACR) was lower in interspecific crossing combinations (6.1%) than intraspecific ones (27.6%). The seed production efficiency (SPE) values were 1.1 and 9.3% for interspecific and intraspecific crosses, respectively. Weather conditions and pollinator's skills are the main contributors to the low success rate in the intraspecific cross combinations in yam breeding. At the same time, genetic distance and heterozygosity played little role. Interspecific cross barriers were both pre-zygotic and post-zygotic, resulting from the evolutionary divergence among the yam species. Dioscorea rotundata had higher interspecific cross-compatibility indices than D. alata. Distant parents produced intraspecific crossbred seeds with higher germination rates compared to closest parents (r = 0.21, p = 0.033). This work provided important insights into interspecific and intraspecific cross-compatibility in yam and suggested actions for improving hybridization practices in yam breeding programs.

水稻小粒不育系新组合卓两优141混播制种优势分析

<p id="C3">Traditional hybrid breeding is backward, low benefit, and high cost, which restricts the promotion and application in hybrid rice. However, Small Grain TMS lines are easy to be mechanically separated after mixed-sowing and mixed-harvesting. Their application will promote the realization of complete Mechanization of Hybrid Rice Seed Production, leading to the reduction of cost and the improvement of seed production efficiency. In this study, we investigated the agronomic characteristics and outcrossing rates suitable for Mechanization of Hybrid Rice Seed Production, using the Small Grain male sterile line Zhuo 201S, Large Grain restorer line R141, and their combination Zhuoliangyou 141 as materials for mixed-sowing and large-scale seed production practice. The results demonstrated that compared with the control TMS C815S, Zhuo 201S plants were shorter, exhibiting longer and more erect ear, fewer glume opening, lower percentage of panicle enclosure and germination on ears. Moreover, Zhuo 201S plants were resistant to smut disease but sensitive to “920” treatment and had weak seed-shattering characteristic. However, R141 plants were tall and insensitive to environmental temperature with large amount of pollen and a long florescence. Both Zhuo 201S and R141 had good outcrossing characteristics. The grain thickness of Zhuo 201S and R141 was 1.71 mm and 2.23 mm, respectively. The 1000-grain weight of Zhuo 201S and R141 was 14.00 g and 28.20 g, respectively. Due to the significant difference in grain sizes, the hybrid F₁ seeds could be easily separated with the male parent seeds through a special sieve with narrow and long apertures. The percentage of male parent seeds mixed in hybrid seeds was 0 while the hybrid seed loss rate was 2.31%, suggesting that the seed purity met the standards for Mechanization of Hybrid Rice Seed Production. Compared with the traditional seed production mode, the basic seedling of male parent was reduced by 85%, the capacity of female parent was increased by 20%, the seed production yield was increased by 21.37%, and the comprehensive benefit of seed production was increased by 31.4%. Zhuoliangyou 141 was endowed with the advantages suitable for mechanized production by mix-sowing, with excellently agronomic traits and outcrossing properties along with huge difference in grain size from its parents. Therefore, the whole process of Zhuoliangyou 141 mechanized seed production had a broad application prospect.

Factors Associated with the Technical Efficiency of Maize Seed Production in the Mid-Hills of Nepal: Empirical Analysis

Maize is the second most important staple crop in Nepal. Its demand is rapidly increasing due to a growth in the poultry sector. The national maize yield is low, leading to insufficient domestic production and thereby increasing imports. Maize seed is considered as one of the crucial inputs in achieving the targeted yield growth, but usually is in short supply during the cropping season. Farmers are involved in maize seed production, which eases its supply. Thus, understanding the efficiency of maize seed production will have a direct impact on the efficiency of the country’s maize production. This paper aimed to assess the technical efficiency (TE) of maize seed production and the major factors affecting TE. Semistructured questionnaire survey was administered in June 2016 to 182 maize seed farmers selected randomly from a total of 260 maize seed growers in Palpa District, a leading maize seed producing district in the mid-hills of Nepal. TE is estimated based on the stochastic frontier production model, and the factors affecting TE are assessed using the Tobit model. TE ranged from 0.25 to 0.92 with an average of 0.71. This revealed the scope of increasing TE by 29%. TE in the study area is largely affected by the age and schooling year of household heads. Similarly, the experience of maize seed production, livestock holding, the share of maize seed area, seed source, and access to extension services affect TE. Hence, a focus on motivating experienced educated maize seed growers to expand the maize seed production area supplemented by a better seed source and extension services would contribute to improving TE.

Ефективність виробництва насіння та перспективи розвитку насінництва в Україні

Ефективність виробництва насіння та перспективи розвитку насінництва в Україні

Combining ability and heterosis in egusi-melon &lt;i&gt;Citrullus lanatus&lt;/i&gt; (Thumb.) Matsum and Nakai

This study was carried out to evaluate the genetic potential of seven egusi-melon genotypes for seed weight and its components following the diallel mating scheme. Seven parents were selected from among 28 genotypes obtained from indigenous farmers in five ecological zones (forest, derived savanna, southern, northern and Sudan savanna) of Nigeria. The experiment was laid out in a completely randomized block design with four replications. Specific combining ability variance was of greater importance than general combining ability variance in the inheritance of all the traits under study. Okwe-2-IM x KTGO-GMB was the best combiner for number of pods and pod weight per plant while KOGI-NITN x MOKWA-NG was the best combiner seed weight per plant. Positive and highly significant (P<0.01) heterosis was recorded among crosses for number of primary vines, number of pods and seed production efficiency per plant indicating their importance in hybrid development for improved yield.

The Efficiency of Hybridization and Seed Production in Musa spp

The Efficiency of Hybridization and Seed Production in Musa spp

Optimal ammonia concentration for fertilization success in Pinctada martensii (Dunker) under the simultaneous influence of temperature and salinity

Pinctada martensii is one of several important pearl oysters. Ammonia is typically added to the seawater and used during artificial reproduction to improve the fertilization rate. However, the optimal ammonia concentration has not been determined. To determine the optimal ammonia concentration for fertilization success, the effect of the ammonia concentration on the fertilization rate in P. martensii was investigated under the simultaneous influence of temperature and salinity. A Box-Behnken design and response surface method were used in this study. The results showed that the ammonia concentration had a significant effect, which varied quadratically with the ammonia concentration in the ranges of the factor regimes (P < .01). The interactions between the ammonia concentration and the temperature/salinity had a significant effect (P < .05), indicating that the effect of the ammonia concentration depended on the combination of temperature and salinity; therefore, their combined effects should be taken into account when determining the optimal ammonia concentration. The effect of the ammonia concentration was less than that of the temperature but more than that of the salinity. A reliable model of the fertilization rate using the three factors was constructed. The results of the model optimization demonstrated that a fertilization rate of 96.16% was achieved at an ammonia concentration of 1.85 mmol L−1 and a temperature-salinity combination of 27 °C/32 practical salinity unit (psu). The ideal fertilization rate was verified experimentally using the optimal ammonia concentration while maintaining the temperature and salinity at natural levels during the spawning season. The results of this study can be used to refine the seed production efficiency of the pearl oyster.