普通小麦×硬粒小麦杂种蛋白质含量及其电泳分析

本文分析了普通小麦×硬粒小麦杂种14个选系的籽粒蛋白质含量及7个选系籽粒氨基酸组成。科春_(14)×D_(213)杂种7个选系的平均蛋白质含量为18.45%,比双亲平均数(15.04%)高。肯尼亚×阿波罗各选系蛋白质含量比其亲本平均提高3.44%。籽粒中氨基酸含量随着籽粒蛋白质含量的提高而增加。选系 KA_(20)的蛋白质含量为20.13%,比母本     

不同麦区小麦籽粒蛋白质与氨基酸含量及评价

为了解我国小麦品种氨基酸营养状况,收集了2009-2011年22个省655份小麦籽粒样品,分析其蛋白质以及18种氨基酸含量。样品中春小麦和冬小麦籽粒蛋白质平均含量分别为13.7%和12.7%。春小麦符合强、中、弱筋蛋白质标准的样品分别占45%、22%和33%,而冬小麦样品的比例分别为18%、24%和58%。除酪氨酸外,春小麦各测定氨基酸组分的含量均高于冬小麦,但必需氨基酸占总氨基酸的比例二者均为28.8%。小麦籽粒蛋白质含量呈现出北高南低、东高西低的趋势,必需氨基酸含量和总量则呈现出东高西低的趋势。有98%的样品以赖氨酸、2%的样品以色氨酸为限制性氨基酸。春、冬小麦氨基酸评分平均值分别为53和56,年度间有差异。在本研究取样区域内,小麦籽粒蛋白质水平整体较低,尤其是必需氨基酸赖氨酸含量和必需氨基酸占比低,限制了小麦蛋白质的营养价值。     

小麦产量与品质性状杂种优势的研究

本试验在河南省从北到南4个不同纬度的地点上连续进行2年(共8个环境类型).材料包括7个小麦亲本和由此按不完全双列杂交模式组配、人工去雄授粉产生的12个杂种组合.研究结果,小麦杂种单株籽粒产量平均杂种优势及其变异幅度分别为22.01%、11.90—40.64%.每穗粒数的杂种优势大于千粒重和单株穗数的杂种优势.面团形成时间,面团稳定时间,拉伸仪面积、峰值、延伸度及其拉伸仪峰值与延伸度的比值均呈现正向杂种优势;籽粒蛋白质含量、吸水率、面筋含量和弱化度表现负向杂种优势.但单株籽粒蛋白质产量表现正向杂种优势,平均17.20%.容重表现正向杂种优势,且变异范围较窄.杂种优势的环境变异主要是受地点以及地点、年份和杂种间二级互作的显著影响.     

绵阳系列小麦籽粒蛋白质含量及其组分与SDS-沉降值关系的研究

以14个绵阳系列小麦品种为材料,研究不同品种籽粒蛋白质含量、蛋白组分和SDS-沉降值的变化规律,以及籽粒蛋白质含量及其组分与SDS-沉降值的关系,为绵阳系列小麦品种的选育提供理论依据。研究结果表明,不同小麦品种籽粒蛋白质含量不同,变幅为7.30%~13.09%,多数品种属于低蛋白质含量类型。多数品种的SDS-沉降值分布在20~30 mL范围内。不同品种籽粒蛋白组分各异。籽粒蛋白质含量、贮藏蛋白含量、谷蛋白和醇溶蛋白含量都与SDS-沉淀值成极显著的正相关关系。高的籽粒蛋白质含量和谷蛋白与醇溶蛋白含量是绵阳系列小麦品种获得较好烘烤品质的前提。     

花后高温和水分逆境对小麦籽粒蛋白质形成及其关键酶活性的影响

以2个蛋白质含量不同的小麦品种扬麦9号和豫麦34为材料,在人工气候室条件下研究了花后高温和水分逆境对小麦籽粒蛋白质合成关键酶活性及籽粒蛋白质组分含量的影响。结果表明,籽粒蛋白质及其组分含量显著受温度、水分和温度×水分互作的影响,且温度的影响大于水分及温度×水分的影响。高温提高了籽粒蛋白质含量,但降低了谷/醇比。无论高温或适温下,干旱胁迫均提高籽粒蛋白质含量。谷/醇比在适温干旱下升高,高温干旱下降低;渍水降低籽粒蛋白质含量和谷/醇比。籽粒蛋白质含量在高温干旱下最高,适温渍水下最低。在温度和水分逆境下,籽粒醇溶蛋白和谷蛋白的变化是导致蛋白质含量和谷/醇比差异的主要原因。高温和水分逆境均降低旗叶谷胺酰氨合成酶（GS）和籽粒谷-丙转氨酶（GPT）活性,不同温度条件下酶活性均表现为对照>干旱>渍水。高温和水分逆境对蛋白质合成关键酶活性的影响在不同品种间存在差异,适温下,豫麦34旗叶GS活性易受水分的抑制;扬麦9旗叶GS活性易受高温的抑制。高温下,豫麦34旗叶氮代谢受高温影响较大,而扬麦9则更易受水分胁迫影响。     

休闲期深松配施氮肥对旱地土壤水分及小麦籽粒蛋白质积累的影响

为探索旱地小麦休闲期蓄水保墒及其配套施肥技术,2009-2011年连续2个小麦生长季,在山西闻喜县进行了休闲期深松或无耕作条件下低(75 kg hm^-2)、中(150 kg hm^-2)、高(225 kg hm^-2)施氮水平的田间试验,以明确深松处理配合施氮对土壤水分、籽粒蛋白质形成的影响。结果表明,深松处理可提高播前土壤蓄水量,尤其是深层土壤(60~160 cm)蓄水量,欠水年和丰水年分别提高12%~34%、10%~22%。深松处理后,籽粒谷氨酰胺合成酶(GS)、旗叶谷氨酸合酶(GOGAT)、低氮和中氮条件下籽粒GOGAT、籽粒谷丙转氨酶(GPT) 活性均提高;籽粒蛋白质产量和球蛋白含量,及丰水年谷蛋白含量和谷醇比也提高。随施氮量增加,开花期20~200 cm土壤蓄水量呈下降趋势,但籽粒GS、灌浆中后期旗叶GOGAT、灌浆后期籽粒GPT活性均上升,籽粒蛋白质及其组分含量提高,中氮条件下籽粒谷醇比最高。施氮量对深松处理开花期深层土壤蓄水量、籽粒蛋白质产量、籽粒GS和GPT活性有较大调控效应。深松配施氮肥条件下,丰水年开花期土壤水分与籽粒清蛋白、谷蛋白、蛋白质含量关系密切,而欠水年开花期土壤水分与谷醇比关系密切。氮代谢酶主要影响籽粒球蛋白含量、蛋白质产量的积累,丰水年还影响籽粒谷蛋白含量和谷醇比的提高。总之,旱地小麦休闲期深松蓄水效果好;配施氮量225 kg hm^-2有利于提高籽粒蛋白质及其组分含量,在欠水年施氮量150 kg hm^-2有利于提高籽粒蛋白质产量及谷醇比。     

153份小麦品种(系)品质性状初步分析

以153份小麦品种(系)为材料,采用近红外光谱技术对其籽粒蛋白质含量、湿面筋含量、硬度进行了检测。结果表明,59.4%小麦品种(系)的蛋白质含量大于14.0%,26.1%小麦品种(系)的蛋白质含量介于13.0%~14.0%之间。湿面筋含量大于32.0%的小麦品种占22.8%,湿面筋含量大于28.0%而小于32.0%的小麦品种(系)占45.7%;9.1%小麦品种(系)的籽粒硬度大于60;90.8%小麦品种(系)的籽粒硬度在40~60。有45个小麦品种(系)的蛋白质含量、湿面筋含量和籽粒硬度可初步评定为强筋麦,占参试品种数29.4%。另有79个品种(系)为中筋麦,其余的29个为弱筋麦。这表明,参试品种(系)绝大多数仍以中筋麦为主。     

膜侧施肥对旱地小麦产量、籽粒蛋白质含量和水分利用效率的影响

覆膜栽培能提高旱地小麦产量,但降低了籽粒蛋白质含量,优化施肥是解决这一问题的有效措施之一。2013年9月至2016年9月,在黄土高原中部典型旱地进行田间定位试验,比较传统平作(不覆盖+均匀施肥)、垄覆沟播(垄上覆膜+垄间沟播+均匀施肥)和膜侧施肥(垄上覆膜+垄间沟播+播种行侧膜下定位施肥)栽培模式下,0~40 cm土层硝态氮含量和0~200 cm土壤水分,以及膜侧施肥对小麦氮素吸收利用、产量、籽粒蛋白质含量和水分利用的影响。与传统平作相比,在偏旱的2013—2014和2015—2016年度,垄覆沟播的小麦产量分别提高9.5%和6.3%,籽粒蛋白质含量降低7.1%和9.9%,水分利用效率提高5.8%和8.7%,而膜侧施肥的小麦产量提高18.8%和22.8%,籽粒蛋白质含量无显著变化,水分利用效率提高13.2%和19.6%;在偏湿润的2014—2015年度,垄覆沟播和膜侧施肥对小麦产量无影响,但膜侧施肥的籽粒蛋白质含量和水分利用效率分别提高6.0%和17.0%。与垄覆沟播相比,膜侧施肥在偏湿润年份使生长季内100~200 cm土壤水分消耗显著减少,而在偏旱年份使夏休闲季土壤蓄水显著增加,开花和收获期0~40 cm土壤硝态氮、根系全氮以及开花期茎叶全氮含量升高,促进了小麦营养器官氮素吸收、积累及其向籽粒的转运,提高了旱地小麦产量,籽粒蛋白质含量和水分利用效率。在偏干旱的2013—2014和2015—2016年度,膜侧施肥较垄覆沟播产量分别提高8.4%和15.5%,籽粒蛋白质含量提高9.9%和8.7%,水分利用效率提高7.0%和10.0%;在偏湿润的2014—2015年度,两处理产量无显著差异,但膜侧施肥的籽粒蛋白质含量提高6.0%。因此,膜侧施肥可维持旱地小麦生育后期的土壤氮供应,提高小麦产量、籽粒蛋白质含量和水分利用效率,增加下季播前深层土壤贮水,是适宜于旱区推广的小麦栽培模式。     

宽幅播种对强筋小麦籽粒产量、品质和氮素吸收利用的影响

宽幅播种与适宜种植密度合理组配能够提高小麦籽粒产量和氮素利用率。然而,在协同改善产量和氮素利用率的同时,宽幅播种对籽粒品质有何影响未见报道。本研究于2018—2019和2019—2020连续2个生长季,选用藁优5766、济麦44、泰山27、洲元9369等4个强筋小麦品种,设置宽幅播种和常规条播2种播种方式,研究了宽幅播种对强筋小麦籽粒产量、品质和氮素吸收利用的影响。结果表明,宽幅播种条件下,主要得益于单位面积穗数的增加, 4个强筋小麦品种的单位面积粒数平均增加13.16%,籽粒产量相应提高13.39%。与此同时,宽幅播种强化了整个生育期特别是花后氮素的吸收,整个生育期小麦植株氮素积累量平均增幅为10.29%,花后氮素吸收量平均增幅为36.83%,进而提高了氮素吸收效率和氮素利用率,平均增幅分别为12.73%、13.39%。整个生育期特别是花后氮素吸收的增加,保障了籽粒氮素供应,提高了单位面积籽粒氮积累量,且其提高幅度(平均增幅为13.38%)与单位面积粒数(平均增幅为13.16%)和籽粒产量(平均增幅为13.39%)的提高幅度相近,籽粒单粒含氮量和蛋白质含量得以保持不变,籽粒蛋白质构成...     

灌浆期温度对两种类型小麦籽粒蛋白质组分及植株氨基酸含量的影响

以扬麦9号和徐州26两个蛋白质含量不同的小麦品种为材料,利用人工气候室模拟灌浆期高温环境,研究了高温对小麦籽粒蛋白质组分和植株游离氨基酸含量的影响。结果表明,高温处理显著提高了小麦籽粒蛋白质及清蛋白、球蛋白和醇溶蛋白含量,但降低了谷蛋白含量,导致麦谷蛋白/醇溶蛋白比值降低。与适温处理相比,高温提高了地上部营养器官中游离氨基酸含量,显著降低了灌浆后期籽粒游离氨基酸含量。表明高温下提高的营养器官游离氨基酸含量及籽粒对氨基酸的快速利用是籽粒蛋白质含量增加的生理原因。此外,发现籽粒中蛋白质及其组分形成所需的适宜昼夜温差随不同小麦品质类型而异。     

Combining ability analysis and association of yield and yield components among selected cowpea lines

The study was carried out to determine combining ability and association of yield and yield components among crosses derived from seven selected cowpea (Vigna unguiculata (L.) Walp) parents. Twenty-one hybrids were generated from diallel crosses excluding reciprocals. Hybrids along with seven parents were studied for combining ability and phenotypic correlations for seed yield and eight yield components. The result indicated that the general combining ability (gca) and specific combining ability (sca) were significant for most characters indicating the importance of both additive and non-additive genetic components. Additive gene action was important for eight characters except pod number, whereas non-additive gene action was not important for nodule number and grain yield. Parental lines IT86D-716 and IT81D-985 were found to be good general combiners for grain yield and other traits. The most promising specific combiners for yield and yield components were from crosses including IT87D-697-2 × IT86D-716, IT88D-867-11 × IT86D-716, IT93K-624 × IT87D-697-2, and IT87D-697-2 × IT92KD-405-1. Significant positive phenotypic correlations were observed between seed yield with pod length (POL), number of pods per plant (PON), and number of seeds per pod (SPD). POL, pod number per plant, SPD, and grain yield were identified as the best selection criteria that could be used in cowpea breeding programs.     

多棱饲用大麦品系粮、草产量及品质的鉴定与综合评价

为培育适宜沿江、江淮地区种植的粮（籽粒）和草（饲草）产量及品质优良的大麦新品种，对12份多棱饲用大麦新品系和对照品种西引二号的饲草和籽粒的产量及品质进行比较，运用灰色关联度分析法进行综合评价。结果表明，B11015-1干草产量显著高于大部分自育品系，但与对照差异不显著；多个自育品系的籽粒产量高于对照，其中B11015-7籽粒产量最高；B11015-7和B11015-3饲草粗蛋白含量较高，分别为7.96%和7.82%；B11015-2和B11015-14相对饲喂价值（RFV）较高，分别为159.15和157.14；B11015-3和皖饲2-1籽粒蛋白质含量较高，分别为10.33%和10.03%。采用灰色关联度分析，以10个性状指标对参试品种（系）进行综合评价，初步认为B11015-3、B11015-1、B11015-2和B11015-14等4个自育品系优于对照，可能成为沿江、江淮等地种植的粮、草兼用多棱饲用大麦材料。     

Agronomic and quality characteristics of spring wheat lines selected for protein content and protein yield

Summary High protein cultivars of spring wheat (Triticum aestivum L.) from eight foreign countries and the United States were used in crosses to provide progeny for a recurrent selection program. After two cycles of selection, 40 lines selected for protein yield and 16 lines selected fro protein percentage were evaluated with parents in yield nurseries at Bozeman, Montana.Lines selected for protein pereentage had the highest protein percentages, protein yields similar to the parents, and grain yields lower than the parents. Lines selected for protein yield had protein percentages intermediate between those of the parents and lines selected for protein percentage, but they had the highest protein yields and grain yields. Protein percentage and grain yield were negatively correlated and protein yield and grain yield were positively correlated for both groups of lines. The data tend to suggest that protein yield may a better selection criterion than protein percentage for plant breeders to use in improving protein productivity, although additional testing of this hypothesis is proposed.Milling and baking data showed transgressive improvement over the mean of the patents in many important quality aspects, indicating that good quality lines can be obtained from crosses involving poor to mediocre quality cultivars.Joint contribution of ARS, USDA and the Mont. Agric. Exp. Stn. Published with approval of the Director of the Mont. Agric. Exp. Stn. as Paper No. 1181, Journal Series. Received 19 June 1981.     

Genetic response to index selection for grain yield, kernel weight and per cent protein in four wheat crosses

Quantitative genetic theory was used to investigate selection differentials, expected and observed direct and correlated responses to simultaneous improvement of grain yield, kernel weight, and grain protein content in F₃ and F₄ populations of four spring wheat (Triticum aestivum L.) crosses. Selection in the F₃ generation based on the Smith-Hazel index (SH) and yield was found to be superior to the other methods studied in identifying high-yielding lines, but resulted in substantial decrease in grain protein level. Consequently, a 1.0% increase in protein from selection for protein depressed grain yield as much as 536 kg/ha below the population mean, reducing the expected yield gains per generation selection cycle by 250%. The weight-free indices (EW), particularly the index involving only yield and kernel weight (EW3) and its linear approximation (EW4), and the desired gains indices were effective in improving protein content but were less efficient in selecting top-yielding lines. Selection in the opposite direction using truncation of the lowest 10% of the population based on weight-free-index involving yield, kernel weight and protein (EW2) reduced all traits significantly compared with the mean of the unselected population indicating the effectiveness of the unweighted selection index. The observed genetic gains (Ra) from selection based on yield, the SH, EW3 and EW4 indices were slightly lower than the expected advances per cycle (R) in populations from crosses ‘Sinton’בGlenlea’ (C1), ‘Glenlea’בNB505’ (C2), and ‘A2P5’בNB320’ (C6) (Ra/R = 70 to 85%) but were higher in cross ‘NB505’בA2P5’ (C5) (Ra/R = 126 to 143%). It was concluded that weight-free and the desired gains indices can be used to improve wheat grain yield and grain protein simultaneously in F₃ generation selection, as revealed by response to selection measured in the F₄ generation.     

The ND EarlyQPM program: developing the next generation of healthier maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) products

There is a need to develop the next generation of healthier crop products for an improved human and animal nutrition. Maize (Zea mays L.) cultivars with improved amino acid profiles are essential to diets focused on this crop. Breeders have added crop value with the development of quality protein maize (QPM). However, QPM cultivars have never been an option to farmer and ranchers in short-season environments. The objectives of this research were: (1) to adapt QPM genotypes to the northern U.S. through the North Dakota (ND) EarlyQPM Program, and (2) to develop new early generation SS and non-SS short-season QPM lines and populations for breeding purposes. Fifty-three inbred lines, including 47 QPM donor lines, five experimental North Dakota State University (NDSU) lines, and one ex-PVP line from industry, were selected to produce 94 early-QPM backcross populations. Considering earliness, protein content, and amino acid levels, 218 early generation lines were selected for producing testcrosses with industry testers. Experiments evaluating testcrosses were arranged in 10 × 10 and 12 × 12 partially balanced lattice designs across three ND locations in 2013 and 2014. A total of 48 lines were selected for further development, 17 representing the Stiff Stalk (SS) heterotic group and 31 representing the non-SS group. Selected lines showed, in hybrid combinations, not only above average grain yield, rate of dry down, and total protein content but also high levels of lysine, tryptophan, and methionine essential amino acids for feedstock nutrition. The results of this research show, for the first time, the successful adaptation of QPM genotypes to short-season environments. As a result, new ND EarlyQPM germplasms and lines have been developed for potential release.     

Protein yield of oats as determined by protein percentage and grain yield

Summary Relationships among the traits protein percentage, grain yield, and protein yield of oats were studied with F₂-derived lines in F₃ and F₄ from 27 matings obtained by crossing high-protein with high-yield oat lines. High-protein parents were (a) selections from an Avena sativa bulk, (b) selections from three-way matings in which an initial parent was A. sterilss, and (c) cultivars. High-yield parents were derived from backcross populations involving A. sterilis accessions as donor parents.Significnnt genetic variation existed among F₂-derived lines for grain and protein yield in all matings and for protein percentage in all but one mating.Protein percentage had a highly significant negative correlation with grain yield (r=–0.33^**) when pooled over all matings, but in five, these two traits were not correlated. Overall, protein percentage showed a small negative correlation with protein yield (r=–0.09^*), and protein and grain yields had a high positive association (r=0.98^**). F₂-derived lines with both high protein percentage and high grain yield were obtained.High transgressive segregates for protein percentage occurred in two matings, for grain yield in nine, and for protein yield in 14. Most high transgressive segregates for protein yield were high because of high grain yield only, but in four matings, lines were found where protein yield was increased by concurrent increases in both protein percentage and grain yield.Only a few specific parental combinations between high-protein and high-yield parents produced segregates in which increased protein percentage contributed materially to high-protein yields.Journal Paper No. J-11264 of the Iowa Agriculture and Home Economics Experiment Stn., Ames, Iowa 50011. Project 2447.     

品种混种控制小麦白粉病及其对小麦产量和蛋白质含量的影响

研究品种混种对控制小麦白粉病的效果以及对产量及蛋白质含量的影响,可为利用品种多样性持续控制白粉病提供理论依据及技术支持。2011—2012和2012—2013年度选用抗病性不同、遗传背景有较大差异的8个小麦生产品种,按每个组合3~8个品种进行田间混种,人工接种白粉菌混合菌株,比较品种混种对小麦白粉病的病害流行曲线下面积以及小麦产量、粗蛋白含量和千粒重的影响。结果表明,混种组分品种的数量对防效有影响,其中以4个品种混种的防病效果最好,但当品种数达到7个及以上时,混种也显示出较好的控病效果。2011—2012年度混种组合中有防效的占42.4%,相对防效为1.2%~26.8%,约50%的混种组合表现增产,增产幅度为0.2%~14.6%;2012—2013年度有防治效果的组合占75.0%,相对防效1.8%~45.4%,约71%的混种组合表现增产,增产范围为0.9%~16.6%。供试品种中周麦18总体表现最好,并且与其他品种混种后对控制小麦白粉病、增加产量和粗蛋白含量均有正向效应。不同混种组分品种间存在互作,其互作对病害控制及产量均有影响。     

Indica-Japonica differentiation of paddy rice and its relationship with heterosis

The Indica‐Japonica differentiation of three photoperiod‐sensitive and/or thermosensitive genetic male‐sterile rice (PGMS or TGMS, respectively) lines and 47 male parental lines from seven ecotypes were studied for their restriction fragment length polymorphism marker data to determine which ecotype crosses with the three PGMS and/or TGMS lines could lead to higher yield potential, and to estimate the relationship between the Indica‐Japonica differentiation of parents and heterosis in grain yield and its components. The results indicated that hybrids derived from ‘N422s’ and the early‐middle ripening Indica varieties from southern China, and hybrids between ‘Pei'ai64s’ and three Japonica ecotypes, including North‐eastern Japonica varieties, restoring lines of Japonica hybrid rice and north China Japonica varieties, showed the highest grain yields. There was less variation of yield among the F1s between ‘108s’ and the seven ecotypes than among the other F₁s. Highly significant positive correlations between heterosis of the F₁ yield and genetic distance of the parents were detected, although the correlation between F₁ yield performance and genetic distance did not reach a significant level. Considerable variation of correlation between heterosis and genetic distance was also detected in the Indica × Indica crosses and Indica × Japonica crosses. There was much higher correlation (r = 0.63) between the F₁ yield performance and the genetic distance of parents in the Indica × Indica crosses than in the others. It is proposed that a genetic distance of 0.4‐0.8 between the two parents of hybrid rice might be appropriate not only for F₁ performance, but also for heterosis.     

Development of unique and novel lines for early-maturing hybrids: moving GEM germplasm northward and westward

Future maize (Zea mays L.) genetic gains are dependent on the incorporation of unique and useful genetic diversity to breeding programs actively improving germplasm and developing cultivars. Our ultimate goal is to increase the genetic diversity currently available in early maturing maize hybrids by developing novel lines that can be utilized competitively in the northern US Corn Belt. A long-term breeding project (EarlyGEM) was initiated to move US Germplasm Enhancement Maize (GEM) germplasm northward and westward. Nine out of 152 breeding crosses were adapted and data from one breeding cross is presented. Five hundred BC₁:S₁ lines derived from (AR16026:S17-66-1-B × ND2000) × ND2000 were advanced, selected, and crossed to several commercial testers for early and late generation hybrid testing. Experiments were arranged in various partially balanced lattice designs and grown across 23 North Dakota (ND) environments. Data showed experimental GEM-derived hybrids had better grain yield (10.4 vs. 9.2 t ha^?1), test weight (72.5 vs. 70.1 kg h L^?1), extractable starch (67.8 vs. 64.2%) and fermentable starch, grain oil (4.3 vs. 3.5%), and grain protein (10.5 vs. 9.4%) when compared to popular hybrids at similar grain moisture at harvest. This is the first research incorporating GEM-derived tropical and late-temperate genetic materials for inbred line development representing a relative maturity (RM) below 90 days. As a consequence of these breeding efforts GEM materials were adapted to the northern US Corn Belt and are not only sources of useful and unique novel genetic diversity but also competitive products for industry use as requests for experimental EarlyGEM lines have been extensive. This research has practical implications with regards to new ways of conducting maize breeding for high latitudes.