Selection efficiencies for improving drought/salt tolerances and yield using introgression breeding in rice(Oryza sativa L.)

The backcross(BC) breeding strategy has been increasingly used for developing high yielding varieties with improved abiotic stress tolerances in rice. In this study, 189Huang-Hua-Zhan(HHZ) introgression lines(ILs) developed from three different selection schemes were evaluated for yield related traits under drought stress and non-stress conditions in the target and off-season winter nursery environments to assess the selection efficiency of BC breeding for improving different complex traits, and led us to five important results. The first result indicated that the primary target traits should be selected first in the target environments(TEs) in order to achieve the maximum genetic gain. Secondly, BC breeding for drought tolerance(DT) in rice was almost equally effective by strong phenotypic selection in the main target environments and in the winter-season of Hainan.Thirdly, exploiting genetic diversity in the subspecific gene pools is of great importance for future genetic improvement of complex traits in rice. Fourthly, considerable genetic gain can be effectively achieved by selection for secondary target traits among the ILs with the primary traits. Finally, the developed ILs provide useful materials for future genetic/genomic dissection and molecular breeding of complex traits.

Development of Hybrid Rice Variety FY7206 with Blast Resistance Gene Pid3 and Cold Tolerance Gene Ctb1

Hybrid rice Fanyou 7206（FY7206）, derived from the cross between a sterile line Fanyuan A and a restorer line Fuhui 7206, was bred by the Rice Research Institute, Fujian Academy of Agricultural Sciences, China. FY7206 was characterized by moderate blast resistance, cold tolerance, as well as wide adaptability, and high yields. The blast resistance results indicated that the frequencies of blast races in race B, race C and the total resistance frequency for FY7206 were 95.5%, 100.0% and 97.2%, respectively. The disease resistance results showed that the leaf blast grade for FY7206 was level 1 and panicle blast was level 5. The indoor spray results indicated that FY7206 was resistant to 11 isolates of Magnorpathe oryzae. The blast resistance of FY7206 might be derived from the high expression of blast resistance gene Pid3. The results for simulated cold resistance in an artificial climate chamber indicated that the cold tolerance for FY7206 was moderate at the booting and flowering stages. The cold tolerance results also indicated that FY7206 could be tolerant to temperatures as low as 10 °C at the seedling stage. The q RT-PCR results showed that the expression of cold tolerance gene Ctb1 in FY7206 was relatively high. These results suggested that FY7206 is a hybrid indica rice variety with good comprehensive characteristics, including blast resistance and cold tolerance.

Selective footprints and genes relevant to cold adaptation and other phenotypic traits are unscrambled in the genomes of divergently selected chicken breeds

Background The genomes of worldwide poultry breeds divergently selected for performance and other phenotypic traits may also be affected by,and formed due to,past and current admixture events.Adaptation to diverse environments,including acclimation to harsh climatic conditions,has also left selection footprints in breed genomes.Results Using the Chicken 50K_CobbCons SNP chip,we genotyped four divergently selected breeds:two aboriginal,cold tolerant Ushanka and Orloff Mille Fleur,one egg-type Russian White subjected to artificial selection for cold tolerance,and one meat-type White Cornish.Signals of selective sweeps were determined in the studied breeds using three methods:(1)assessment of runs of homozygosity islands,(2)F_(ST) based population differential analysis,and(3)haplotype differentiation analysis.Genomic regions of true selection signatures were identified by two or more methods or in two or more breeds.In these regions,we detected 540 prioritized candidate genes supplemented them with those that occurred in one breed using one statistic and were suggested in other studies.Amongst them,SOX5,ME3,ZNF536,WWP1,RIPK2,OSGIN2,DECR1,TPO,PPARGC1A,BDNF,MSTN,and beta-keratin genes can be especially mentioned as candidates for cold adaptation.Epigenetic factors may be involved in regulating some of these important genes(e.g.,TPO and BDNF).Conclusion Based on a genome-wide scan,our findings can help dissect the genetic architecture underlying various phenotypic traits in chicken breeds.These include genes representing the sine qua non for adaptation to harsh environments.Cold tolerance in acclimated chicken breeds may be developed following one of few specific gene expression mechanisms or more than one overlapping response known in cold-exposed individuals,and this warrants further investigation.

Identification Cold Tolerance of Pineapple Germplasms at Seedling Stage

Pineapple plant was always injured due to low temperature. Breeding varieties with high cold tolerance was the supreme way to resolve this problem and identifying cold tolerance of germplasms collected was necessary. In this study, SSR locus around homologous sequences of cold-tolerant genes was searched and screened using MD-2 (cold-tolerant variety) and Tainong 17 (cold-sensitive variety). Seventy three pairs of primers of which PCR results were different between these two varieties were gotten. PCRs were performed using these as primers and genomic DNA of germplasms collected as templates. Six pairs of primers were found that their PCR results were in good consistent with cold tolerance. Using GLM (General linear model) association mapping analysis, two SSR markers linked to cold tolerance were found. Their efficiency was verified further using pineapple germplasms with high cold tolerance which had been validated in field by cold wave. They will be used in cold-tolerant breeding of pineapple in the future.

Drought-Tolerant Rice at Molecular Breeding Eras:An Emerging Reality

Rice(Oryza sativa L.)stands as the most significantly influential food crop in the developing world,with its total production and yield stability affected by environmental stress.Drought stress impacts about 45%of the world’s rice area,affecting plants at molecular,biochemical,physiological,and phenotypic levels.The conventional breeding method,predominantly employing single pedigree selection,has been widely utilized in breeding numerous drought-tolerant rice varieties since the Green Revolution.With rapid progress in plant molecular biology,hundreds of drought-tolerant QTLs/genes have been identified and tested in rice crops under both indoor and field conditions.Several genes have been introgressed into elite germplasm to develop commercially accepted drought-tolerant varieties,resulting in the development of several drought-tolerant rice varieties through marker-assisted selection and genetically engineered approaches.This review provides up-to-date information on proof-of-concept genes and breeding methods in the molecular breeding era,offering guidance for rice breeders to develop drought-tolerant rice varieties.

The effects of selection for cold tolerance on cross-tolerance to other environmental stressors in Drosophila melanogaster

Cross tolerance, whereby tolerance to one environmental stress is correlated with tolerance to other stressors, is thought to be widespread in insects. We used lines of Drosophila melanogaster Meigen （Diptera： Drosophilidae） selected for survival at a 1-h exposure to -5℃ to examine the extent to which this selection results in increased tolerance to other stresses, including high and low temperatures, desiccation and starvation. While selection improved tolerance to acute cold exposure and survival at -5℃, there was little effect of selection regime on tolerance to other stressors. There was no correlation between tolerances to any of the stressors, suggesting different mechanisms of tolerance. This supports arguments that correlations between stress tolerances during selection experiments with D. melanogaster may be coincidental. The magnitude of heat-hardening was apparently constrained by basal tolerance among lines, but the magnitude of the rapid cold-hardening response was not correlated with basal cold tolerance, implying that the relationship between inducible and basal tolerances differs at high and low temperatures.

优质甜玉米骨干系在低温下种子萌发及幼苗抗性研究

甜玉米普遍存在种子发芽率低及对低温敏感的问题。为探明甜玉米种子发芽和幼苗对低温耐受性,本研究选取12份甜玉米骨干自交系,分别于25、18和12℃温度下测定萌发相关生理指标,结合相关性及聚类分析,筛选出低温萌发优势材料;选取5份优势材料开展幼苗4℃低温处理,进行耐寒相关生理指标比较及耐寒基因表达分析。结果表明,随着温度的下降,12份甜玉米骨干自交系的发芽率、发芽势、发芽指数和活力指数均受到不同程度抑制,其中发芽变幅分别为82.5、75.8和62.5个百分点;方差分析结果表明,发芽率和发芽势在温度、品种及温度与品种间互作效应均存在极显著差异;在18和12℃下,8个耐低温发芽能力单项指标表明,发芽率、发芽势、发芽指数和活力指数两两之间存在显著相关,性状聚类分析将12品种分为3类,分别为耐冷型、一般型和敏感型,筛选出闽甜系T146(1-46)、闽甜系L18(L18)、12hi307(307)、闽甜系JR8609(JR86)、闽甜系AS67(AS67)、闽甜系X9034(X90)和闽甜系AG87(AG87)为具有较好的耐低温萌发能力的优势材料。针对1-46、L18、307、JR86和AS67进行幼苗低温处理,其中L18幼苗的丙二醛(MDA)含量显著低于其余4份材料,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性表现相反;抗寒基因表达分析结果发现,ZmCesA2、ZmCesA10和ZmDREB1.7在AS67和L18中表达较高,ZmMPK2在L18中表达最低;综合分析结果表明,闽甜系L18和闽甜系AS67具有较强耐低温能力。本研究结果一方面丰富了甜玉米耐寒性理论研究,另一方面为耐寒新品种选育提供了良好的材料资源。

水稻耐低温研究进展

水稻是世界上的主要粮食作物之一,低温将导致水稻发育延缓,长期遭受低温胁迫易导致水稻枯萎死亡。全球每年约有1 500万hm^(2)的水稻面临低温胁迫危害,低温冷害已成为水稻减产的主要原因之一。为系统了解水稻耐低温机理研究进展,总结了低温对水稻细胞结构特征的影响、低温对水稻生理生化特性的影响、水稻耐低温优良品种选育和水稻耐低温的分子机理的研究现状,并展望了水稻耐低温品种的未来选育方向。

荷花品种“西湖秋韵”和“湘湖秋韵”的培育与扩繁应用

“西湖秋韵”和“湘湖秋韵”是以荷花品种“西湖红莲”为父本,“秋艳”和“秋星”为母本,通过授粉杂交方法选育出的具有一定耐寒性且花期较长的荷花品种。本文总结分析了2个荷花品种的选育过程、品种形态特征、生物学特性及其扩繁应用,为耐寒且花期长荷花品种的繁育与应用提供参考。“西湖秋韵”和“湘湖秋韵”2个品种均为大株型,展花期分别能持续到10月中旬和11月中旬。二次栽植后,“湘湖秋韵”品种展花期可延长至12月10日。“西湖秋韵”和“湘湖秋韵”的群体花期分别达154和133 d,具有花色鲜艳、花瓣大及对环境适应性强等优点,可广泛应用于湿地公园建设、河道和湖滨水景绿化改造及小区水体美化等场域。

高含油抗病耐寒油菜新品种浙农油12的选育

浙农油12是一个高含油、抗菌核病和病毒病、耐寒性好的油菜新品种,由浙江勿忘农种业股份有限公司自主选育,并于2023年通过非主要农作物品种登记,登记编号:GPD油菜(2023)330235,适宜在长江下游浙江、江苏、安徽、上海冬油菜区秋冬季节种植。该品种以具有适性广、品质高的3个油菜品种为基础材料,通过杂交组合测配和世代材料分离,以聚合抗主要病害、耐低温冻害、高含油量等优势农艺和品质性状为定向选择目标,通过系谱法多年选育而成。该品种多点适应性试验平均产量2 813.5 kg·hm^(-2),比对照增产2.7%;含油量49.71%,硫苷含量21.48μmol·g^(-1),无芥酸。

水稻低温冷害分析研究进展

冷害是水稻减产的主要原因之一,也是全世界普遍关注的问题。从水稻耐冷机理、耐冷资源的评价与利用、耐冷相关基因的定位和克隆以及水稻耐冷基因工程等方面对水稻耐冷性研究进行了阐述,并对今后水稻耐冷研究和育种工作提出了一些建议。

抗旱耐盐型小麦品种沧6001的选育

沧 60 0 1小麦品种是用临汾 6154作母本 ,冀麦 32作父本通过有性杂交 ,经两圃平行交替选择法培育而成。该品种突出的特点是抗旱、耐盐、抗寒、优质、丰产稳产。这些优良特性的结合 ,丰富的遗传背景 ,逆境和非逆境选种环境以及杂种后代交替选择育种技术起了决定性作用。

大菱鲆(Scophthalmus maximus)耐高温品系选育及耐温性能评估

采用家系选育方法,进行了大菱鲆耐高温性状选育研究,对两代家系耐温性能进行测定,并利用bCOX回归分析了各家系的耐温性优势比。结果表明:各家系耐温性差异达到了显著水平(P<0.05),并且耐高温能力的优势比也存在显著差异,这反映出在大菱鲆耐高温选育中家系选择的高效性;经过一代选育,获得4个耐高温家系,并据此构建选育二代家系。耐温性能评估,选育二代比一代有显著提高,在27℃高温条件下,选育一代的平均死亡率为49%,选育二代的平均死亡率为10.26%;28℃条件下,选育二代耐高温子代的平均死亡率为32.83%,对照组的平均死亡率为88.9%;经过筛选后,选育二代的耐温性比选育一代提高了1—2℃左右。

新品种高寒鲤的选育

从1979年开始，用了约15年时间，采用杂交和雌核发育技术相结合的方法，成功地将黑龙江野鲤的耐低温、荷包红鲤耐高密度养殖和镜鲤生长快等优良性状综合到三杂交种中，建立了Ⅰ、Ⅱ两个选育系，再用它们与野鲤和镜鲤回交，从6个回交种中选出2个与Ⅰ、Ⅱ两个雌核发育系组合成合成系并系统选育到F7，育成了抗寒力达97．6％（H1IF6），生长速度比当地养殖鲤快近一倍的高寒鲤。研究中发现黑龙江野鲤的抗寒因子可以转移给杂种，并稳定地遗传给后代；与野鲤回交可同时加强抗寒能力和提高生长速度，以及采用雌核发育技术与常规结合，可加速选育速度。

甘农一号杂花苜蓿品种选育报告

以提高抗寒性、越冬性为日标,开展黄花苜蓿和紫花苜蓿的杂交育种。配制多个人工杂交组合,利用黄花苜蓿开放传粉杂种并引进杂种品种,在高寒地区进行抗寒筛选,采用改良混合选择法,选育出以82个无性系为基础综合而成的抗寒品系“甘农杂18”。通过品种比较试验、区域试验、生产试验表现良好,定名为“甘农一号”杂花苜蓿。

利用籼稻资源中的“隐蔽有利基因”提高粳稻苗期耐冷性

苗期低温是制约东北水稻生产的一个重要逆境因子,培育苗期耐低温的水稻品种是解决这一问题最有效的途径之一。以粳型恢复系C418为轮回亲本与7个来自不同地域的供体杂交和回交培育BC2F2群体,利用沈阳春季田间自然低温进行耐冷筛选,并对入选的177个苗期耐冷导入系后代在自然和人工气候室两种不同强度的低温胁迫条件下的苗期表现进行评价。结果表明,虽然供体亲本均为苗期耐冷性弱的品种,但在全部回交后代中均出现耐冷性的超亲分离,表明这些供体亲本均携带对耐冷性有利的"隐蔽基因",但组合间的耐冷性选择效率存在较大差异。以人工气候室低温胁迫后的存活率为耐冷性鉴定指标,导入系之间出现广泛分离,田间筛选入选比例高的BG300和中413导入系群体中,出现存活率高的导入系后代比例较其他群体高,说明在同一轮回亲本遗传背景下回交后代的耐冷水平取决于供体。在室内严格低温条件下表现为强耐冷性的导入系在相对温和的自然低温胁迫下表现为苗高、苗干重较非胁迫条件生长抑制不明显,且能够促进根系生长。结果表明,大量的耐冷有利基因以"隐蔽"的形式存于水稻种质资源中。通过利用来源广泛的种质资源作为供体进行回交育种,对回交后代进行严格耐冷筛选,可有效选育高产耐冷水稻品种和有价值的育种材料。

寒地水稻花培育种选择效率分析

对25年寒地水稻花培育种与同期常规育种统计资料进行了比较分析。经花培入选的产量鉴定新品系的选择效率为16．94％，是同期常规新品东选择效率11．34％的1．49倍；经花培育成的审定品种的选择效率为o93％，是同期常规育成审定品种选择效率o．28％的3．32倍。从花培育成品种的推广种植面积与常规育成品种比较分析，花培育种与常规育种有同样好的选择效果。

植物体细胞耐盐突变体的研究进展

植物体细胞耐盐突变体研究已经成为抗盐植物育种学研究的热点问题。综述了植物耐盐体细胞突变体筛选的试材确定、突变体筛选方法和突变体鉴定的研究现状,并指出植物耐盐突变体筛选还存在着变异类型复杂,变异方向难以控制,耐盐细胞系难以再生植株等缺陷。应加强高效稳定的植株再生体系建立;加强细胞悬浮培养技术研究,提高耐盐突变体筛选效率;提高耐盐目标性状的变异频率,减少非目的性状变异产生;从不同层面上加强耐盐突变体基础研究,提高突变体检测效果等方面研究,以提高植物体细胞耐盐突变体育种效果,更好地为实践和生产应用。

玉米抗旱育种的研究进展

干旱已经对粮食安全构成了巨大的威胁。玉米抗旱育种是减少干旱造成产量损失的重要途径。本文介绍了一些抗旱的玉米种质资源和选育抗旱玉米品种的方法。轮回选择法是玉米抗旱育种经济有效的方法,在进行轮回选择的过程中运用数学方法评价产量性状,通过第二性状进行玉米抗旱辅助选择,引入权重法构建合理的抗旱模型。回顾和展望了生物技术在玉米抗旱育种中的应用及前景。

水稻耐寒育种研究进展

水稻冷害是一个长期威胁着包括中国在内的世界上许多国家粮食安全的重要问题。概述了水稻冷害的危害性及冷害的类型和发生机理,并对国内外水稻耐寒育种的理论研究和实践进行了详细回顾与总结,从几个方面重点阐述了中国水稻耐寒育种研究的理论方法与实践应用。结合水稻耐寒育种目前存在的局限探导了未来发展的策略,最后提出了今后在水稻耐寒育种领域的发展趋势。