Quantitative Trait Loci for Heading Date and Their Relationship with Genetic Control of Yield Traits in Rice (Oryza sativa)

Grain yield and heading date are key factors determining the commercial potential of a rice variety. Mapping of quantitative trait loci （QTLs） in rice has been advanced from primary mapping to gene cloning, and heading date and yield traits have always attracted the greatest attention. In this review, genomic distribution of QTLs for heading date detected in populations derived from intra-specific crosses of Asian cultivated rice （Oryza sativa） was summarized, and their relationship with the genetic control of yield traits was analyzed. The information could be useful in the identification of QTLs for heading date and yield traits that are promising for the improvement of rice varieties.

Effects of Planting Date on Winter Canola Growth and Yield in the Southwestern U.S.

Canola (Brassica napus L.) has potential to become alternative cash crop (healthy oil for human and meals for animal uses) with tremendous rotational benefits in the Southwestern U.S., a region dominated by cereal-fallow cropping systems. However, information on optimum planting date for its successful production is limited. Field experiments were conducted in 2011-12 and 2012-13 seasons under irrigation condition to study the response of canola growth and yield to planting dates at Clovis, NM. Three planting dates (mid-September, late-September and early-October) and four canola varieties (early flowering: DKW41-10 and DKW46-15;medium flowering: Riley and Wichita) are studied. Fall plant stand density is significantly higher for early-October than mid- and late-September plantings. However, a ratio of fall to spring plant stand density indicates a greater reduction in spring plant stand density with early-October (25%) and mid-September (19%) than late-September (7%). Vegetative (by 13 days) and flowering (by 7 days) duration phases are significantly shortened with delay in planting. The decline in aboveground dry matter (DM) due to delayed planting resulted in significant seed yield reduction in both 2011-12 (26%) and in 2012-13 (8%) when early-October and mid-September plantings were compared. There was a positive relationship between final DM and canola seed yield, accounting for 84 and 34% variation for 2011-12 and 2012-13 seasons, respectively with the 2011-12 environmental conditions being conducive for genetically controlled variation in DM production to be more apparent and strong in explaining the variation in seed yield among varieties. Medium-flowering varieties produced higher DM (9741 vs. 8371 Kg•ha-1) and seed yield (2785 vs. 2035 Kg•ha-1) than early-flowering varieties. In addition to seed yield, DM can be used as an indirect selection criterion for seed yield in variety selection and appropriate planting dates including a guarantee for high crop residues (~75% of the total aboveground biomass) production to make canola a potential alternative cash and rotational break crop in the Southwestern U.S.

Effects of planting dates and shading on carbohydrate content,yield,and fiber quality in cotton with respect to fruiting positions

Two cotton（Gossypium hirsutum L.） cultivars, Kemian 1（cool temperature-tolerant） and Sumian 15（cool temperaturesensitive） were used to study the effects of cool temperature on carbohydrates, yield, and fiber quality in cotton bolls located at different fruiting positions（FP）. Cool temperatures were created using late planting and low light. The experiment was conducted in 2010 and 2011 using two planting dates（OPD, the optimized planting date, 25 April; LPD, the late planting date, 10 June） and two shading levels of crop relative light rate（CRLR, 100 and 60%）. Compared with fruiting position 1（FP1）, cotton yield and yield components（fiber quality, leaf sucrose and starch content, and fiber cellulose） were all decreased on FP3 under all treatments. Compared with OPD-CRLR 100%, other treatments（OPD-CRLR 60%, LPD-CRLR 100%, and LPD-CRLR 60%） had significantly decreased lint yield at both FPs of both cultivars, but especially at FP3 and in Sumian 15; this decrease was mainly caused by a large decline in boll number. All fiber quality indices decreased under late planting and shading except fiber length at FP1 with OPD-CRLR 60%, and a greater reduction was observed at FP3 and in Sumian 15. Sucrose content of the subtending leaf and fiber increased under LPD compared to OPD, whereas it decreased under CRLR 60% compared to CRLR 100%, which led to decreased fiber cellulose content. Therefore, shading primarily decreased the ＂source＂ sucrose content in the subtending leaf whereas late planting diminished translocation of sucrose towards cotton fiber. Notably, as planting date was delayed and light was decreased, more carbohydrates were distributed to leaf and bolls at FP1 than those at FP3, resulting in higher yield and better fiber quality at FP1, and a higher proportion of bolls and carbohydrates allocated at FP3 of Kemian 1 compared to that of Sumian 15. In conclusion, cotton yield and fiber quality were reduced less at FP1 compared to those at FP3 under low temperature and low light conditions. Thus, reduced cotton yield and fiber quality loss can be minimized by selecting low temperature tolerant cultivars under both low temperature and light conditions.

Growth and Yield of Guar (Cyamopsis tetragonoloba L.) Genotypes under Different Planting Dates in the Semi-Arid Southern High Plains

Guar is a drought and salt tolerant summer annual legume, which could be a potential alternative crop in the semi-arid Southern High Plains. Increased use of guar gum in oil industries has increased the demand of guar globally. Planting date effects on stand establishment, physiological parameters, and yield formation of guar genotypes were investigated at the New Mexico State University’s Agricultural Science Center at Clovis, NM for two seasons (2014 and 2015). Four guar genotypes (HES 1123, Kinman, Lewis, and Matador) were tested under three planting dates (June 18, July 7, and July 22 in 2014;and June 18, July 6, and July 20 in 2015). Higher temperature and rainfall were recorded under mid-June planting than early-July and late-July plantings. Guar planted under mid-June had better stand establishment as shown by the higher number of plants m-2, better physiology as revealed by higher photosynthetic rate (Pn), transpiration rate (Tr), leaf area index (LAI), and SPAD values than early-July and late-July plantings. Guar planted under mid-June resulted in taller plants, and therefore, produced higher plant biomass than both of the July plantings. Yield attributing characteristics including clusters plant-1, pods plant-1, seeds plant-1, seed spod-1, 1000 seed weight, and harvest index (HI) were highest under mid-June planting followed by the early-July and late-July plantings, respectively. The mid-June planting increased seed yield by 26% and 55% over early-July and late-July (1399 vs. 1111 and 903 kg·ha-1) plantings, respectively in 2014;while the same increase in 2015 was 51% and 243% (1308 vs. 868 and 381 kg·ha-1), respectively. These results indicate that delaying planting beyond mid-June is detrimental to guar productivity. However, genotypes did not show any significant variation in their performance. Overall, warmer growing conditions and more precipitation under mid-June planting caused better growth and yield formation of guar genotypes.

Year-to-Year and Maturity Variation in Rainfed Soybean Yield by Planting Dates

The interactions on rainfed soybean yield among planting date, maturity, and year-to-yearclimate change were studied using CROPGRO-soybean model. Simulations were based on 19 plantingdates, maturity groupsⅢ, ⅣandⅤ, 30 years recorded weather data from Corbin, Suffolk,West Point in Virginia, USA. Yield was similar on early plantings and went down with lateplantings. Both grand and year-to-year variation of soybean yield declined linearly withplanting date. Year-to-year climate variation was dominant yield variation source inrainfed soybean production. Interaction occurred between planting date and maturity.Optimal planting dates for different sites lied within 130th-170th day of a year.Irrigation is recommended for profitable crops, especially in Corbin and West Point.

Effect of Different Sowing Dates in South Henan 's Rice-growing Areas on the Growth and Yield of Ratoon Rice

In order to determine the optimal sowing date of ratoon rice in South Henan's rice-growing areas,this paper performs a comparative analysis of rice growth process,seedling quality and yield of first season rice and ratoon rice under different sowing date treatments. The results show that under climatic conditions( 2014),by using dry seedling cultivation in a small plastic shed,the growth of seedling sown on February21 was affected,while the sowing treatments from March 1 to April 11 can breed normal seedlings,and in this period,the maturity period of first season rice was delayed with prolonged sowing date,and ratoon rice yield declined with prolonged sowing date( total production of rice sown on 11 March reaching a peak). Thus,it is considered that the optimal sowing date of ratoon rice in South Henan's rice-growing areas is mid-March.

Effects of Sowing Dates on Yield,Agronomic Traits and Resistance of Millet in Yan'an

[ Objective ] This study aimed to investigate the appropriate sowing dates of different millet varieties and analyzed the yield, agronomic traits and resist- ance of millet. [ Method ] Split-plot design was employed with sowing date and millet variety assigned to the main plot and sub-plot, respectively, to investigate the effects of sowing dates on yield, agronomic traits and resistance of millet. [ Result] The results showed that early or late sowing would lead to yield reduction. Changsheng 07, Jingu 36 and Changnong 35 exhibited higher yield. Based on the yield, agronomic traits and resistance, the appropriate sowing date of Changsheng 07, Jingu 40 and Jingu 36 was May 13 ; the appropriate sowing date of Yangu 13 and Changnong 35 was May 20. [ Conclusion] The most appropriate sowing date of millet in Yan＇an was May 10 to May 20. Key words Millet; Sowing date; Yield; Agronomic traits ; Resistance

Optimization of sowing date and seeding rate for high winter wheat yield based on pre-winter plant development and soil water usage in the Loess Plateau,China

Sowing date and seeding rate are critical for productivity of winter wheat(Triticum aestivum L.).A three-year field experiment was conducted with three sowing dates(20 September(SD1),1 October(SD2),and 10 October(SD3)) and three seeding rates(SR67.5,SR90,and SR112.5) to determine suitable sowing date and seeding rate for high wheat yield.A large seasonal variation in accumulated temperature from sowing to winter dormancy was observed among three growing seasons.Suitable sowing dates for strong seedlings before winter varied with the seasons,that was SD2 in 2012–2013,SD3 in 2013–2014,and SD2 as well as SD1 in 2014–2015.Seasonal variation in precipitation during summer fallow also had substantial effects on soil water storage,and consequently influenced grain yield through soil water consumption from winter dormancy to maturity stages.Lower consumption of soil water from winter dormancy to booting stages could make more water available for productive growth from anthesis to maturity stages,leading to higher grain yield.SD2 combined with SR90 had the lowest soil water consumption from winter dormancy to booting stages in 2012–2013 and 2014–2015; while in 2013–2014,it was close to that with SR67.5 or SR112.5.For productive growth from anthesis to maturity stages,SD2 with SR90 had the highest soil water consumption in all three seasons.The highest water consumption in the productive growth period resulted in the best grain yield in both low and high rainfall years.Ear number largely contributed to the seasonal variation in grain yield,while grain number per ear and 1 000-grain weight also contributed to grain yield,especially when soil water storage was high.Our results indicate that sowing date and seeding rate affect grain yield through seedling development before winter and also affect soil water consumption in different growth periods.By selecting the suitable sowing date(1 October) in combination with the proper seeding rate of 90 kg ha–1,the best yield was achieved.Based on these results,we recommend that the current sowing date be delayed from 22 or 23 September to 1 October.

The Yield and Water Use Efficiency to First Cutting Date of Siberian Wildrye in North China

A field experiment study was conducted in Bashang Plateau in North China in 2008 to determine the effect of three first cutting dates on the growth and water use efficiency （WUE） of Siberian wildrye （Elymus sibiricus L.） in the agropastoral ecotone of North China （APENC）. The experiment was conducted in a split plot design with three replications with water supply regime as the main plot treatment and first cutting date as the subplot treatment. Two water supply regimes were used, which included rain-fed treatment as control （CK） and a single irrigation and straw mulch treatment （W）. Three first cutting date treatments were conducted at early heading stage on July 1 （E）, at late heading stage on July 12 （L）, and at flowering stage on July 27 （F）, respectively. The results showed that the forage yield and WUE were the lowest at early heading stage harvest, while the highest at flowering stage either in CK or W treatment. Under combined CK and W treatments, average forage yields of the F subplots were 2 900 and 6 703 kg ha-~, and the values of WUE were 0.82 and 2.28 kg m-3, respectively. Under the CK treatment, forage yields of the E and L subplots were 43.8 and 41.9% lower than the F subplots, and their values of WUE were 46.2 and 50.3% lower than F, respectively. Under the W treatment, the forage yields of the E and L subplots were 74.9 and 61.6% lower, and their values of WUE were 78.1 and 63.3% lower, respectively, as compared with F subplots. Therefore, earlier first cutting did not increase the regrowth of Siberian wildrye and improve the mismatch between rainy season and the period of high growth potential of the grass in the semiarid APENC.

Effect of tapping tools and date of tapping on Acacia polyacantha gum yield in South Kordofan State, Sudan

A study was conducted in South Kordofan, Sudan to determine the effect of tapping, tapping tools and date of tapping on the gum yield of Acacia polyacantha. A two-factor experiment was conducted for two seasons in 2008-2009. One location was used for two seasons and two locations for one season. The first factor （4 levels） was the tools of tapping： Makmak, Farrar, and Sonki, and the control which was not tapped. The second factor （2 levels） was the date of tapping that comprises mid October and mid November. These treatments were arranged in Randomaized Complete Block Design and replicated three times. Gum yield （g/tree and g/ picking） was recorded for five pickings. Economic analysis was done using the partial budget technique. The results showed highly significant （p 〈 0.01） differences on gum yield （g/picking and g/tree）. The results indicated that the process of tapping increases gum production by 88.4% and 79.8% compared with un-tapped trees, respectively. The date of tapping has no significant effect on gum yield （g/tree and g/picking） of A. polyacantha. Tapping of the tree with Makmak in mid- November was found to be economically beneficial compared to using the other tools and the control. These results could identify a new source of income for the poor farmers in South Kordofan mainly because of the wild occurrence of Kakamut as a potential gum producing tree species grown naturally in the area.

Influence of Date of Transplanting on Growth and Yield Attributes and Resultant Seed Quality of Davana

A field experiment was conducted at TamilNadu agricultural university, Coimbatore during rabi 2011 to study the effect of time transplanting on growth, yield attributes and resultant seed quality of davana. The experiment was laid out with five different dates of transplanting viz., October 15th, November 1st, November 15th, December 1st and December 15th with the spacing of 15 × 7.5 cm and 125:125:75 NPK kg/ha were adopted in a randomized block design with four replications. The results revealed that the seedlings transplanted at 15th November recorded the maximum number of branches/plant, seed yield/plant, seed yield/plot, resultant seed germination and vigour index.

Effect of grass density and date of tapping on Acacia senegal gum yield in north kordofan state, Sudan

We conducted a two-factor experiment in randomized complete block design with four replications during 2004 in El Demokeya Forest Reserve and El Himaira Natural Forest, North Kordofan State, Sudan. The objective was to develop an understanding of the ecological effects of under-story vegetation and tapping date on the productivity of gum arabic from Acacia senegal as over story cover. The first factor was grass cover which was tested in four levels （100% and 50% grass cover in addition to bare and burnt）. The second factor, date of tapping was tested in three levels namely （1st Oct, 15th Oct and 1st Nov）. The first picking was done after 45 days from tapping and the gum yield up to seven pickings was collected at intervals of 15 days. Gum yield from each picking was collected and weighed using sensitive balance. Analysis of variance was carried out using MSTAT-C statistical package, and the Tukey test was applied for mean comparisons. The results showed highly significant differences （p 〈 0.01） of grass cover on gum arabic yield in the two sites for most of the first consecutive pickings （1st–4th out of seven） in addition to total yield （kg/ha）. With exception to the 4th pickings, the interaction effect between the grass densities and tapping date was not significantly different. The total gum yield was significantly （p 〈 0.05） increased in only two pickings （third and fourth） in El Demokeya Forest Reserve and two pickings （1st and 2nd） at El Himaira Natural Forest. The density of grass cover significantly （p 〈 0.05） affected the number of pickings at both sites; the number of gum pickings was directly proportional to grass density. The number of gum pickings was found to be significantly （p 〈 0.05） increased at the early date of tapping.

Yield and Yield Components of Bread Wheat as Influenced by Water Stress, Sowing Date and Cultivar in Sokoto, Sudan Savannah, Nigeria

Field experiments were conducted during 2009/10 and 2010/2011 dry seasons at the Fadama Teaching and Research Farm of the Usmanu Danfodiyo University, Sokoto, in the Sudan Savanna ecological zone of Nigeria (latitude 13°01'N;longitude 5°15'E, altitude of 350 m above sea level) to study the effect of water stress, sowing date and cultivar on yield and yield components of wheat (Triticum aestivum L.). The treatments consisted of factorial combination of water stress at three critical growth stages which was imposed by withholding water at tillering, flowering, grain filling and control (no stress), four sowing dates (21st November, 5th December, 19th December and 2nd January) and two bread wheat cultivar (Star 11 TR 77173/SLM and Kuaz/Weaver), laid out in a split-plot design with three replications. Water stress and date of sowing were assigned to the main-plot, while variety was assigned to the sub-plots. Result revealed that water stress at tillering significantly reduced spike length and grains per spike. Whereas, water stress at flowering and grain filling significantly reduced 1000-grain weight, grain yield and harvest index. Results also indicated significant (P st November and 5th December and lowest at 19th December and 2nd January, therefore wheat should be sown in November or at least first week of December in this area and other area with similar climate. Variety had significant effect on spike per m-2, grain yield and harvest index. Water stress at flowering and grain filling should be avoided as they are the most critical growth stages in yield determination in wheat, because plants cannot recover, while delay in sowing resulted in reduction in yield and yield components. Star II TR 77173/SLM is therefore recommended for the area.

大麦茎、叶、穗对饲草产量及品质的影响

为探明大麦不同组织(茎、叶和穗)在不同刈割期对饲草产量及品质的影响,以安徽省两个主栽饲用大麦品种为材料,比较了两年度两个品种茎、叶和穗分别在齐穗期及其后14 d和28 d饲草产量及品质的差异。结果显示,不同组织、刈割期及组织×刈割期互作效应对饲草产量及品质均有显著影响(P<0.05),年度效应主要影响产量,其他互作效应因品种和性状不同而异。饲草产量随刈割期后移增加,对其贡献表现为茎﹥穗﹥叶,第2年度高于第1年度。饲草品质性状在组织间和刈割期间存在显著差异,而在年度间仅在单个品种若干性状上存在差异;粗蛋白含量表现为穗﹥叶﹥茎,且随刈割期后移下降;粗纤维、酸性洗涤纤维、中性洗涤纤维和酸性洗涤木质素含量均为茎﹥叶﹥穗,且随刈割期后移前3个性状先降后升,酸性洗涤木质素含量持续上升;粗脂肪含量为叶﹥穗﹥茎,且随刈割期后移上升。综上,在株高相当时,增加穗部比例可提高大麦饲草产量和品质;刈割期后移可提升饲草产量但降低品质。基于本研究,选育大穗、多叶型品种,适期刈割,有望同步提升大麦饲草产量和品质。

延迟播种对不同熟期类型油菜新品种产量及相关因子的影响

为了探索湘东地区延迟播种对不同熟期类型油菜品种产量及相关因子的影响,选择湖南省主推的早熟型沣油112、中早熟型捷油8848、中熟型沣油789油菜新品种在浏阳北盛镇开展3个播期的生产试验。结果表明,3个播期的不同熟期品种均能于4月下旬至5月上旬成熟;3个品种M1、M2的生育期相同,而M3的熟期延迟5~7 d,其中捷油8848的3个播期生育期及积温与沣油789的相同;随着播期的推迟,各品种的株高、一次有效分枝数、有效角果数呈下降趋势;3个播期的平均单产M1低于预期、M2最高,M3最低;3个不同熟期类型品种,中熟型沣油789受播期延迟影响较大,产量水平随播期延迟而显著下降,中早熟型捷油8848对播期延迟的敏感性未达到显著水平,而早熟型沣油112以M2的产量水平最高,显著高于M1和M3。

Influence of Climate on Sugarcane Yield in Côte d’Ivoire: Case of the Ferkessédougou Region

This study aims to understand the current climatic trends and explain the possible losses of agricultural yields. To achieve this objective, this work characterized the evolution of extreme temperature indices in the sugar complexes of Ferké 1 and Ferké 2, two stations located in the northern part of C?te d'Ivoire. The onset and cessation dates of the rainy season and the length of the rainy season were investigated. The agricultural and climatic data were obtained from each sugar complex. The period of study ranges from 2002 to 2019 in Ferké 1 and Ferké 2. The results show significant upward trends in extreme temperature indices. The analysis of sugarcane yield associated with the different climatic parameters shows no significant results in general. However, on the Ferkessédougou sugar complexes, the results highlight that maximum and minimum temperatures could be the variables that influence most yield production. The maximum temperature with coefficients of 1.60 and 0.77 at Ferké 1 and Ferké 2 respectively seems to contribute to an increase in yield while the minimum temperature with coefficients of -0.98 and -0.22 at Ferké 1 and Ferké 2 respectively could lead to a loss in yield. The results obtained with the Single Linear Regression (SLR) and the Multiple Linear Regression (MLR) models also highlight the strong influence of minimum and maximum temperatures.

不同水分供应条件下春玉米的适宜播期

春玉米是半干旱区重要的粮食作物,但该区降水少且年际变异大,春玉米产量低而不稳。适宜播期的选择有利于作物稳产高产,但适宜播期会随水分供应条件的变化而变化。本文以半干旱区主栽春玉米品种‘郑单958’为研究对象,使用APSIM-Maize模型探究该区分期播种试验的适宜间隔以及不同水分供应条件下[雨养、灌溉60 mm、灌溉120 mm、灌溉180 mm、灌溉240 mm、潜在条件(灌溉量308 mm)]春玉米的适宜播期范围。结果表明:1)以不同供水条件下春玉米产量的5%分位为差异阈值划分播期时,该地区春玉米分期播种试验和模拟的时间步长建议设定为4 d;2)雨养条件下,干旱年、正常年和湿润年春玉米平均产量分别为0.9 t·hm^(-2)、2.3 t·hm^(-2)和5.5 t·hm^(-2),平均水分利用效率分别为0.4 kg·m^(-3)、0.7 kg·m^(-3)和1.5 kg·m^(-3),潜在条件、灌溉240 mm、灌溉180 mm、灌溉120 mm、灌溉60 mm和雨养条件下的适宜播期范围分别为5月6日—6月2日、5月6—29日、5月10—29日、5月14—29日、5月14—25日和5月14—17日,适宜播期范围随生育期供水量的增加而提前和扩大;3)潜在条件下春玉米产量的气象决定因子是生育期辐射量,灌溉240 mm和180 mm时产量的气象决定因子分别是营养生长阶段辐射量和降水量,灌溉120 mm和60 mm及雨养条件下的产量决定因子均为生育期降水量。本文探究了春玉米的适宜播期及其随生育期供水量的变化规律,研究结果可为半干旱区春玉米适水播种提供理论参考。

基于WMAIP集成模型的华北冬小麦适宜播期与冬前积温下限研究

为明确气候变暖和“双晚技术”背景下华北地区冬小麦的适宜播期,基于WMAIP集成模型,对华北地区冬小麦适宜播期、冬前积温下限及最迟播期进行了分析。研究结果表明,华北地区晚播减产幅度由南向北增大,南部晚播减产幅度最小(<19.5%),中部晚播减产幅度在26.4%以内,北部晚播减产幅度最大,最高可达32.0%。华北地区北部、中部和南部的适宜播期分别在9月25日—10月5日之间、9月30日—10月20日之间和10月10日—11月5日之间。华北地区冬小麦基于高产和高水分利用效率的适宜冬前积温下限分别在497~629℃·d和344~581℃·d之间,并由南部向北部递增。在高产和高水分利用效率条件下,河北、山东、河南大部分地区的最迟播期分别为10月1—13日、10月10—16日、10月22—28日和10月7—19日、10月16—22日、10月31日—11月12日。研究结果可为气候变暖背景下华北地区“双晚技术”的推广和应用提供参考。

播期对我国北方春大豆农艺性状及产量综合影响的研究进展

播期是影响大豆产量的重要农艺措施,适宜的播期可有效平衡生育期内气候条件,满足大豆各生育阶段需求,发挥品种生产潜能,实现优质高产。为明确播期对我国北方春大豆农艺性状及产量的综合影响,文章综述了播期对大豆形态性状、生育期结构、光合特性、产量及产量构成的影响,以期为我国北方春大豆产区合理选择播期补种救灾提供参考和理论依据,助力我国北方春大豆产业高质量发展。