Impacts of Sletr1-1 and Sletr1-2 mutations on the hybrid seed quality of tomatoes

Shelf life is an important breeding trait in tomato, especially for the tomato production in subtropical and tropical regions. Previously we have isolated and characterized ethylene receptor mutants, Sletr1-1 and Sletr1-2 from mutant population based on Micro-Tom cultivar. Sletr1-1 showed insensitivity to ethylene while Sletr1-2 showed reduced sensitivity to ethylene. We also have demonstrated that the traits are useful for extending fruit shelf life of the hybrid tomato cultivars. For commercializing the hybrid cultivars, the seed quality is another important trait. In this study, we evaluated the effects of the Sletr1-1 and Sletr1-2 mutations on the seed quality characteristics of F_1 hybrid lines generated by crossing Sletr1-1 and Sletr1-2 with three commercial tomato cultivars, Intan, Mutiara and Ratna. Sletr1-1 mutation conferred insensitivity to ethylene in the F_1 hybrid seedlings, resulting in negative effects including reduced germination rate, vigor index and emergence speed index. Interestingly Sletr1-2 mutation had almost no effect on the seed quality characteristics of the F_1 hybrid lines, suggesting that Sletr1-2 was suitable for producing high quality of hybrid seeds.

Review of the detasseling techniques for maize(Zea mays L.)hybrid seed production

Maize(Zea mays L.)is a critical staple crop globally,integral to human consumption,food security,and agricultural product stability.The quality and purity of maize seeds,essential for hybrid seed production,are contingent upon effective detasseling.This study investigates the evolution of detasseling technologies and their application in Chinese maize hybrid seed production,with a comparative analysis against the United States.A comprehensive examination of the development and utilization of detasseling technology in Chinese maize hybrid seed production was undertaken,with a specific focus on key milestones.Data from the United States were included for comparative purposes.The analysis encompassed various detasseling methods,including manual,semi-mechanized,and cytoplasmic male sterility,as well as more recent innovations such as detasseling machines,and the emerging field of intelligent detasseling driven by unmanned aerial vehicles(UAVs),computer vision,and mechanical arms.Mechanized detasseling methods were predominantly employed by America.Despite the challenges of inflexible and occasionally overlooked,applying detasseling machines is efficient and reliable.At present,China’s detasseling operations in hybrid maize seed production are mainly carried out by manual work,which is labor-intensive and inefficient.In order to address this issue,China is dedicated to developing intelligent detasseling technology.This study emphasizes the critical role of detasseling in hybrid maize seed production.The United States has embraced mechanized detasseling.The application and development of manual and mechanized detasseling were applied later than those in the United States,but latest intelligent detasseling technologies first appeared in China.Intelligent detasseling is expected to be the future direction,ensuring the quality and efficiency of hybrid maize seed production,with implications for global food security.

DNA methylation modification in heterosis initiation through analyzing rice hybrid contemporary seeds

Heterosis is an important biological phenomenon and widely applied in agriculture.Although many studies have been performed by using vegetative organs of F_(1) hybrid plants,how heterosis (or hybrid vigor) is initiated and formed,particularly the underlying molecular mechanism,remain elusive.Hybrid contemporary seeds of rice indica varieties 9311 and PA64 were innovatively used and analysis of DNA methylome of embryo and endosperm at early developing stages revealed the globally decreased DNA methylation.Genes,especially those relate to hormones function and transcriptional regulation present non-additive methylation.Previously identified heterosis-related superior genes are non-additively methylated in early developing hybrid contemporary seeds,suggesting that key genes/loci responsible for heterosis are epigenetically modified even in early developing hybrid seeds and hypomethylation of hybrid seeds after cross-pollination finally result in the long-term transcriptional change of F_(1) hybrid vegetative tissues after germination,demonstrating that altered DNA methylation in hybrid seeds is essential for initiation regulation and maintenance of heterosis exhibiting in F_(1) hybrid plants.Notably,a large number of genes show non-additive methylation in the endosperm of reciprocal hybrids,suggesting that endosperm might also contribute to heterosis.

Technology for Hybrid Pepper Seed Production in China

History of hybrid pepper seed production, the status of annually balanced production, and innovative techniques for the large-scale seed production in China are reviewed. Helped by the technological breakthroughs in these fields, China has been the largest base for hybrid pepper seed production in the world.

Studies on Seed Setting Stability in Associated with Temperature for a Two-Line Hybrid Rice,Liangyoupeijiu

When being planted in wide areas in southern China (23°23' - 33°23' N, 98°35' - 120°19' E, sea level above 2.7 - 1285 m), Liangyoupeijiu (LYPJ), a two-line hybrid rice combination, showed a seed setting rate of 75.2 - 77.2%, which was lower by 4.3 - 7.5 percent point than that of an indica hybrid rice Shanyou 63 (CK), with similar values of grain yield and coefficients of variation to CK. Sowing during 5-25th of May in Nanjing (32°3' N, 118°48' E), China, LYPJ headed before 4th September, and gave a seed setting rate of 75 - 90%, and grain yield over 1 kg/m2. If the sowing date was delayed to 14 - 15th, June, its heading date would be as late as 17th - 21st September, and seed setting rate would be declined by 10 - 15% in comparison with that on a suitable sowing date. When flowering took place at an average daily temperature range of 13.7 - 28.5℃ for five days, the spikelet fertility (SF) would be increased by 1.9- 10.7%, for each increment of 1℃. The suitable (SF≥90%) and safe (SF≥75%) temperatures for flowering stage were indicated to be 26.5℃ and 22.9℃, respectively. To get a high and stable seed set in cultivating LYPJ, it was recommended that LYPJ would be planted in the areas south of 34癗, and the favorable average daily temperature during flowering stage should be at 26 - 28℃.

Machine Vision Analysis of Characteristics and Image Information Base Construction for Hybrid Rice Seed

Incompletely closed glumes, germination on panicle and disease are three important factors causing poor seed quality of hybrid rice. To determine how many and which categories should be classified to meet the demand for seed in rice production, the effects of various degrees of incompletely closed glumes, germination on panicle and disease on germination percentage at the harvest and after storage for six months were studied by standard germination percentage test. Six categories of seeds with germ (germinated seeds), severe disease, incompletely closed glumes, spot disease, fine fissure and normal seeds were inspected and then treated separately. Images of the five hybrid rice seed (Jinyou 402, Shanyou 10, Zhongyou 27, Jiayou 99 and Ⅱ you 3207) were acquired with a self-developed machine vision system. Each image could be processed to get the feature values of seed region such as length, width, ratio of length to width, area, solidity and hue. Then all the images of normal seeds were calculated to draw the feature value ranges of each hybrid rice variety. Finally, an image information base that stores typical images and related feature values of each variety was established. This image information base can help us to identify the classification limit of characteristics, and provide the reference of the threshold selection. The management of large numbers of pictures and the addition of new varieties have been supported. The research laid a foundation for extracting image features of hybrid rice seed, which is a key approach to future quality inspection with machine vision.

Research on Theories and Techniques of Irrigation for Safeguarding Seed Production of Two-Line Hybrid Rice

By inducing frequency, intensity and duration of lower temperature in the middle and last ten-day periods in August in the rice-growing areas of southern China, increasing temperature for safe seed production was defined as 2℃. During the sensitive period of fertility, characters of panicle height and canopy structure of TGMS rice, Pei＇ai64S, were measured. Results showed that temperature changes caused by irrigation in fields were below 40 cm of rice plant, and heating effect was significant at 20 cm when the temperature was increased by 3.1 ℃. For the present study, the following irrigation techniques were put forth： the water depth of 15-20 cm, current water used, irrigating after 17：00 and bailing at 10：00 in sunny or cloudy weather, irrigating on whole day, in shady or rainy weather, increasing inflows and outflows in large fields. In the present experiment, pollen fertility and self-fertilized seed setting rate accepted that the techniques were feasible and effective for against lower temperature and safeguarding seed production of two-line hybrid rice.

Pump phase transfer and its control in hybrid seeded optical parametric amplifiers

Due to the existence of spatial walk-off and/or group-velocity mismatch effects, pump-to-signal phase transfer becomes inevitable during parametric amplification. We experimentally demonstrate that in hybrid seeded optical parametric amplifiers(OPAs) that include two OPA stages seeded by the signal and idler waves, respectively, the phase of the output signal can be restored to its initial value, although there are spatial and temporal phase fluctuations on the pump source. This method significantly relaxes the requirement for high pump beam quality, which is always very stringent in parametric amplification systems. With the introduction of this scheme into birefringent phase-matching OPAs or chirped-pulse OPAs, it should be promising to achieve intense femtosecond laser pulses that are close to the diffraction limit in space and ultra-high contrast in time, simultaneously.

Effect of Corona Treatment and Dielectric Separation on Seed Vigor of Hybrid Rice

[Objectives] The aim was to investigate the effects of corona field and dielectric separation on the seed vigor of hybrid rice.[Methods] The seeds of 6 hybrid rice varieties were processed with corona field, dielectric separation and corona field ＋ dielectric separation.[Results] When the field intensity was 200 km/m and the processing time was 4 min, the seed vigor was significantly increased. The seed vigor of Y Liangyou 9918 （2014） increased the most, and the germination potential and the germination rate increased by 17 and 12 percentage points respectively compared to the control. Corona field reduced seed conductivity, and for seedlings, it decreased their MDA content, increased proline content, improved peroxidase activity, and enhanced root activity. When the rotating speed of the drum was 30 r/min, the dielectric separation voltage of 4 500 V could achieve good separation effect, and the vitality of seeds at different grades was significantly different. Under the optimized corona field combined with optimized voltage processing of dielectric separation, the seed vigor at all grades from the separation was significantly higher than that of the dielectric separation processing alone. The combined separation processing separated no seeds with germination rate of higher than 80% from the hybrid rice seeds with germination rate of lower than 60%, yet it could effectively separate the seeds with germination rate of higher than 80% from the hybrid rice seeds with germination rate of 65%-70%. After the combined processing, the germination rates of separated Grade I seeds of Wangliangyou 6 （2015）, N Liangyouhuazhan （2015）, Wangliangyou 6 （2016） increased by 20, 15, 20 percentage points from the germination rates of the control, while the germination rates of N Liangyouhuazhan （2016） and Y Liangyou 9918 （2016）, which had the germination rates of higher than 80%, increased by 3 and 9 percentage points from the control, suggesting insignificant separation effect.[Conclusions] This study provided a new technical approach for the processing of hybrid rice seeds.

Dominance of Brassica and No Effects of Raphanus in Mature Seed Production in Intergeneric Hybrid between Brassica rapa ssp. Pekinensis and Raphanus

We succeeded in producing mature seed from a line of Brassica rapa ssp. pekinensis that had been hybridized with Raphanus sativus var. major. Our focus was on dominance of B. rapa ssp. pekinensis;radish (R. sativus var. major) had no influence. Marker tests for similarity showed that the original CR291M-64 x HwiM-2 hybrid was an inbred CR291M-64, rather than a genuine cross;this appears to have resulted from weak self-incompatibility in this strain. The plants from the mature seed bloomed with reddish flowers differently shown up to present. The intergeneric hybrid between Brassica inbred and Raphanus hybrid was very weak in strength compared to the Brassica inbred which was self-pollinated even though the cause of the weak was not identified. The hybrids between Brassica hybrid, dominant and elite recessive, and Raphanus can be developed in large quantities using mature hybrid seed without resorting to ovule culture techniques.

Feasibility Analysis and Policy Recommendations for Production of Hybrid Rice Seed in Foreign Countries

In the economic new normal,production of hybrid rice seed in foreign countries is the necessity for reducing farmland area occupied by seed production,for ensuring national grain security,realizing cost reducing and quality improving of hybrid rice seed,strengthening competitive power at international market,guiding seed industry of China to go out,building transnational seed groups with core competitive power,establishing close relationship with developing countries,promoting the construction of One Belt One Road strategy,serving overall situation of diplomacy,and setting up excellent international image. It is feasible to produce hybrid seed in foreign countries considering( i) high overall national strength of China,( ii) rapid and healthy growth of China's seed industry and increasingly mature hybrid rice seed production technologies,( iii) excellent climatic conditions of foreign host countries of seed production,and( iv) low land and labor price of foreign host countries of seed production. However,there are social and policy risks,technology and trade barrier risks,market,production,and other risks for production of hybrid rice seed in foreign countries. In view of these,it came up with recommendations,including allowing delivering parent seeds of hybrid rice to foreign countries,allowing delivering hybrid rice seed to China,solving the problem of " opening in protection,and protection in opening",and formulating a package of support policies.

气吸式杂交稻单粒排种器研制

针对气力式水稻精量排种器充种不稳定、单粒播种精度不高和播种量大的问题,该研究设计了一种具有矩形吸种孔和辅助充种装置的气吸式杂交稻单粒排种器。根据“吉田优”型杂交稻的长短轴重力分布情况,确定排种盘吸种孔形状;基于CFD-DEM(Computational fluid dynamics,Discrete element method)流固耦合理论,以吸附力为指标,进行5类具有相同面积的吸种孔单因素仿真试验,确定吸附力最大的吸种孔规格为0.8 mm×2.25 mm;以该型吸种孔为基础,选取辅助充种角、工作转速和工作负压为试验因素,以单粒率S、多粒率M和漏播率L为试验指标,开展Box-Bhnken台架试验,对试验结果进行响应曲面分析和多目标优化,得到排种盘辅助充种角为80.90°、工作转速为42.65 r/min、工作负压为621 Pa时,排种器的单粒率为86.91%,漏播率为3.63%。验证试验结果的排种器单粒率为86.36%、漏播率为3.41%,与优化结果吻合。研究结果可为后续气吸式杂交稻单粒排种器的优化设计和直播机整机作业精度的提高提供指导。

鲜食葡萄杂交种子萌发率与亲本及亲本组合的关系分析

【目的】常规杂交育种是葡萄新品种选育的重要方法,通过对15年的鲜食葡萄育种资料进行整理汇总,分析研究不同倍性亲本选择及不同亲本杂交组合配置与杂交种子萌芽率之间的关系,为鲜食葡萄育种实践工作提供参考和借鉴。【方法】以山西农业大学果树研究所2003—2018年间进行常规杂交的45个鲜食葡萄组合为研究对象,对其亲本选择、杂交组合配置和杂交种子萌发率等进行分析。【结果】1)不同倍性亲本选择及不同亲本组合配置,杂交种子萌发率不同。2)以‘瑰宝’作为父本时,杂交种子的萌发率高。3)45个杂交组合中,不同年份、相同父母本杂交种子萌发率不同。4)45个杂交组合中,玫瑰香和红地球是良好的母本材料;瑰宝是良好的父本材料;美人指不是理想的亲本材料。【结论】选择二倍体品种做母本与四倍体品种杂交比用四倍体品种做母本与二倍体品种杂交时更容易获得种子;以四倍体为父母本时,很难得到杂交后代。

Effects of Different Row Ratios of Male and Female Parents and Application Amount of Nitrogen Fertilizer on Hybrid Wheat Seed Production and Its Component Factors

In order to screen suitable high hybrid wheat seed production technology,the split-plot experiment design was adopted and study was carried out about the effects of the different row ratios of male and female parents and application amount of nitrogen fertilizer on hybrid wheat seed production and its component factors. The results showed that the seed production increased with the increase in the number of female parent row. When the row ratio of male and female parents was 2 ∶ 6,the seed production was 3 683. 8 kg/ha; when the application amount of nitrogen fertilization was 50 kg/ha,the seed production was 3 649. 4 kg/ha; the interaction between the row ratio of male and female parents and the application amount of nitrogen fertilizer indicated that when the row ratio of male and female parents was 2∶ 6 and the application amount of nitrogen fertilizer was 300 kg/ha,the seed production reached the highest( 4160. 6 kg/ha). The row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the component factors of seed production,including the number of grains per spike,spike weight and setting percentage. When the row ratio of male and female parents was 2∶ 5,the number of grains per spike,spike weight and setting percentage were the highest at 26. 7 grains,1. 12 g,and 62. 6% respectively; when application amount of nitrogen fertilizer was 450 kg/ha,the number of grains per spike,spike weight and setting percentage were the highest at 26. 0 grains,1. 08 g,and59. 2% respectively; the interaction of row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the number of grains per spike,spike weight and setting percentage; when the row ratio of male and female parents was 2∶ 5 and the application amount of nitrogen fertilizer was 300 kg/ha,the number of grains per spike,spike weight and setting percentage were the highest at 29. 6grains,1. 24 g,and 71. 6% respectively. The number of grains per spike is the largest component factor for seed production. Increasing the number of grains per spike can increase the seed production. According to the effects of row ratio of male and female parents and application amount of nitrogen fertilizer on the component factors of seed production,the optimal condition was 2∶ 5-2∶ 6 for row ratio of male and female parents and 300-450 kg/ha for application amount of nitrogen fertilizer.

不同化控剂处理对杂交大豆制种催熟效果的影响

为解决杂交大豆种子商业化生产过程中,母本持绿,无法机械化收获、种子皱缩,品质较差的问题,从而推进杂交大豆产业化的进程,系统研究了不同类型化控剂及处理方法对杂交大豆制种过程中母本催熟效果的影响。结果表明:3种不同类型化控剂均可加速茎叶脱水,促进植株成熟,催熟速率排序为:乙烯利<草甘膦<敌草快,化控剂浓度越大,催熟效率越高;R6期喷施草甘膦和敌草快导致籽粒无法正常发育,若晚于R7期喷施,各化控剂催熟效果均不理想,R6+7 d为最佳喷施时期,可解决不育系茎叶持绿、籽粒皱缩、百粒重过大等问题。草甘膦为内息传导型催熟药剂,喷施草甘膦会严重降低种子芽率,无法应用于种子生产,乙烯利、敌草快无此负面作用。综合考量催熟效果、环境安全及操作便利性等方面,敌草快在R6+7 d时期处理可有效促进植株成熟,加速茎叶脱水落叶,降低百粒重,保证种子品质,符合机械化收获要求。

A Method for Rapid Identification of Ningza 11 Seeds Purity with SSR Markers

[Objective] This study aimed to establish a method for rapid identification of Ningza 11 seeds purity with SSR markers. [Method] Taking Ningza 11 hybrid seeds as experimental materials, a method for rapid identification of hybrid rape-seeds was established with SSR molecular markers; meanwhile, the test seeds were planted in the field for comparison and verification. [Result] A method for rapid identification of Ningza 11 seeds purity with SSR molecular markers was estab-lished： DNA from seeds germinated in the night was extracted by alkaline lysis method; the PCR amplification was performed for 2 h, and electrophoresis for 1.5 h, and a silver staining for 10 minutes. It took less than one day to from obtaining sampling seeds to obtaining the purity identification result, so a skil ed professional can complete the detection of at least 6 ×96 = 576 seeds per weekday. By using this set of detection system, the measured purity of seeds from nine samples was extremely significantly positively correlated to the actual purity identified in the field test, with a correlation coefficient of up to 0.984 （P〈0.01）. [Conclusion] This SSR-PCR molecular identification system can be applied for rapid and accurate identifi-cation of Ningza 11 hybrid seeds.

冬水田轻简化栽培杂交稻蓄留再生稻产量形成特点

【目的】轻简化栽培水稻因具有良好的社会、经济和环境效益而受到了广泛的关注。探明再生稻系统下轻简化栽培对杂交稻头季、再生季产量形成特点的影响,可为再生稻轻简化栽培提供理论依据。【方法】于2021-2022年在四川省典型再生稻区泸州进行大田试验,以7个杂交稻(益两优94、德优6699、泰优1060、蓉7优680、乐3优2275、德优727、锦丰优727)和1个常规稻(金农丝苗)为材料,研究两种栽培方式(免耕直播、免耕抛秧)对杂交稻头季、再生季产量形成特点的影响。【结果】栽培方式和品种基因型对杂交稻头季、再生季及两季总产量影响显著。与免耕抛秧相比,免耕直播头季、再生季及两季总产量分别增加了3.52%~7.37%、18.94%~47.37%、7.04%~14.93%,免耕直播杂交稻蓄留再生稻的增产优势主要表现在有效穗数、结实率、干物质积累量和收获指数上。不同基因型杂交稻头季产量以泰优1060、锦丰优727较高,再生季产量及两季总产量则以泰优1060最高。从2年平均值来看,高产杂交稻(德优6699、泰优1060、德优727、锦丰优727)头季、再生季以及两季总产量分别为8.80、2.53、11.33t/hm^(2),较中低产杂交稻(益两优94、蓉7蓉680、乐3优2275)分别增加了13.54%、6.03%、11.76%;比高产常规稻(金农丝苗)分别增加了9.97%、21.87%、12.41%。与高产常规稻相比,中低产杂交稻头季产量平均降低了3.15%,但其再生季及两季总产量则分别平均增加了14.94%、0.58%。从产量构成来看,高产杂交稻头季、再生季的有效穗数、千粒重均高于高产常规稻。从干物质生产来看,与高产常规稻相比,高产杂交稻头季和再生季成熟期的干物质量、收获指数分别平均增加3.82%和11.16%、5.45%和5.70%。中低产杂交稻头季成熟期干物质积累量低于高产常规稻是其减产的主要原因。【结论】再生稻系统下免耕直播相对于免耕抛栽有明显的增产优势,是其源库协调的一种良好响应。综合考虑再生季产量与两季总产量,四川省冬水田区再生稻轻简化高产栽培适宜选用分蘖能力强、千粒重大的杂交稻品种。

早熟高产杂交水稻组合两优7871的选育及其高产栽培和制种技术

两优7871是由178S和R71杂交选育的杂交水稻品种,具有早熟、抗倒伏、优质、高产和稳产等特点。本文总结分析了该品种的选育过程、特征特性、高产栽培及制种技术,该品种在2016—2017年长江中下游区域试验中,全生育期130 d,平均产量9.51 t/hm^(2),外观品质优,适口性、抗病性较好;其高产栽培注重培育壮秧,控制无效分蘖,争取有效穗数,促大穗,提高结实率,重点防治稻瘟病、稻飞虱等;制种技术要点包括合理安排播差期,培育壮秧,合理密植,加强田间管理和巧喷赤霉酸生长调节剂等。研究结果为该品种在长江中下游作为一季中稻、麦茬直播稻和再生稻种植提供参考。

海南两系杂交稻制种适宜区域与时段选择

掌握两系杂交稻在海南制种的气象灾害风险,是科学合理安排两系杂交稻制种生长期的重要依据。针对两系杂交水稻制种过程中的3个关键阶段(育性敏感安全期、抽穗扬花授粉安全期和灌浆安全期)的气象灾害概率进行分析,通过数据分析和实例验证得出各地区制种的安全时段,以及需重点考虑的气象灾害。海南两系杂交水稻育性敏感安全期可安排在3月上旬至4月中旬,三亚、陵水地区从3月上旬开始;乐东、东方、昌江从3月下旬至4月上旬开始;临高在4月中旬至下旬左右,不同界限温度变化略有先后。各地花期的阴雨天气较为随机且概率较小;临高、昌江地区制种重点关注灌浆安全期干热风等危害,提早播种。目前海南水稻制种区域和时段合理,可根据不育系材料不育起点温度阈值和耐受低温时间长短,适当调整播种时段。

福建两系杂交稻制种安全高产的精细气候适宜性区划

利用福建省67个国家气象观测站1971-2020年气象资料以及地理信息资料、两系杂交稻制种基地调查资料,构建了两系杂交稻制种育性转换敏感期气候风险模型与风险等级指标、扬花授粉期天气综合危害指数模型与等级指标两个安全期气候区划指标,选择不育系育性转换起点温度23℃开展研究,基于两系杂交稻制种气候适宜性分区等级标准,采用多层复合方法,开展基于GIS的福建省两系杂交稻制种安全高产精细气候适宜性区划。结果表明:育性敏感期安排在7月上旬-下旬、7月中旬-8月上旬,扬花授粉期安排在8月上旬-中旬,适宜区分布在福建北部、西南部等县市海拔300m以下的区域,次适宜区分布在福建北部、西南部等县市海拔300-500m的区域;育性敏感期安排在7月下旬-8月中旬、8月上旬-下旬,扬花授粉期8月下旬-9月上旬,适宜区分布在福建北部、西南部等县市海拔400m以下的区域,次适宜区分布在福建北部、西南部等县市海拔400-500m的区域;育性敏感期安排在7月上旬-8月下旬,扬花授粉期安排在8月上旬-9月上旬,低适宜区分布在海拔500-1000m的区域,不适宜区分布在海拔1000m以上区域。