【作者】 王雨；

【导师】 余四斌；

【作者基本信息】 华中农业大学 ， 作物生物技术， 2008， 硕士

【摘要】 氮、磷是作物生长发育所必需的大量元素。氮、磷的缺乏是限制作物产量的重要因素。在过去几十年里,作物育种工作者一直致力于以高产为目标的育种研究,注重选育高肥条件下的高产品种。化肥的使用与高产品种的结合,有力地推动了农作物增产。但化肥的大量使用与肥料的低利用率之间的矛盾造成了能源的巨大浪费,提高了作物生产成本,同时这些过剩的肥料会造成严重的环境污染。剖析作物营养吸收利用的遗传基础,提高作物营养吸收利用效率,是解决以上各种问题的重要途径。本研究以两套水稻染色体片段代换系(CSSLs)为材料,按增广设计种植并在大田栽培条件下作正常、低氮和低磷三种处理,全生育期考察株高、穗长、单株有效穗和单株产量,分析代换系对低氮、低磷胁迫反应的差异,并结合分子标记连锁图谱进行QTL定位分析。主要结果如下:1.正常处理下的株高、穗长、单株有效穗和单株产量与它们在两种胁迫处理下的相对系数间均呈极显著负相关,表明存在一种趋势:正常处理下生长量较小的代换系材料对低氮、低磷胁迫的耐性往往较强。但也有一些代换系的绝对生长量和相对生长量都比高亲还大。2.利用9311遗传背景代换系在三种处理下检测到14个株高QTLs、8个单株有效穗QTLs和18个单株产量QTLs。株高QTLs中效应最大的Qph-5b解释表型差异为32.5%,加性效应为19.0;8个单株有效穗QTLs全部呈负向效应,解释表型差异在-42.6%～-62.9%之间;单株产量QTLs中效应最大的Qyd-4c解释表型变异为-88.1%,加性效应为-9.6。利用珍汕97遗传背景代换系在三种处理下检测到28个株高QTLs、19个单株有效穗QTLs和20个单株产量QTLs。株高QTL中效应最大的Qph-1d解释表型差异为68.9%,加性效应分别为24.2。单株有效穗QTLs中效应最大的Qpn-5解释表型差异为58.9%,加性效应分别为2.3。单株产量QTLs中效应最大的Qyd-11a解释表型差异为137.9%,加性效应为6.9。3.两套染色体片段代换系的导入片段均来自日本晴,只是遗传背景不同。但两种遗传背景(9311,珍汕97)下定位的QTLs的数目有很大差异,9311遗传背景代换系在三种处理下共检测到58个QTLs,而珍汕97遗传背景代换系在三种处理下共检测到93个QTLs;不同遗传背景下定位的QTLs的位置大多数是不同的,仅在RM472、RM211、RM7、RM411等区域定位到12个相同位点的QTLs。QTLs数目和位置的差异,说明不同遗传背景对QTLs的表达有很大影响。在不同遗传背景下均检测到的QTLs,一方面说明其存在的真实性,另一方面也反映了其稳定性,这种特性在分子标记辅助选择(MAS)中尤为重要,可能直接应用于育种。4.以9311遗传背景代换系在三种处理下同时检测到Qph-1c、Qph-5b、Qyd-4c等3个QTLs;以珍汕97遗传背景代换系在三种处理下同时检测到Qph-5b、Qph-6、Qph-11a等11个QTLs。这些在正常、低氮和低磷处理下同时检测到的QTLs,表明其不易受胁迫条件(低氮、低磷)的影响,可能更为直接的参与了性状的形成。低磷和低氮处理下同时检测到(正常处理未检测到)18个QTLs,其中9311及珍汕97遗传背景代换系各检测到9个。含有这些QTLs的材料对氮、磷胁迫的反应一致,这些QTLs可能处于水稻对氮、磷吸收利用的相同遗传途径上。大多材料对氮、磷胁迫的反应不同,多数QTLs仅在低磷或低氮处理下被检测到,表明水稻对氮、磷吸收利用遗传机制有很大的不同。5.相对性状反映材料对低氮或低磷胁迫的敏感程度,是衡量实验材料对胁迫环境耐性强弱的一项指标。两套代换系共检测到44个相对性状QTLs,其中28个与两种处理(低磷、低氮)下检测到的QTLs位置相同,16个与两种处理下分别检测到的QTLs位置不同,表明相对性状QTLs并不能完全由两种胁迫处理下检测到QTLs所解释,材料对胁迫耐性的遗传基础也不能完全用不同处理下检测到QTLs来描述和剖析。如Qryd-3b是珍汕97遗传背景代换系检测到的相对单株产量QTL,与低磷、低氮胁迫处理下分别检测到的QTLs位置不同。含有该QTL的代换系在低磷胁迫处理下的相对产量(系数)比珍汕97高0.3,表现出对低磷胁迫的耐性。更多还原

【Abstract】 Nitrogen and phosphorus are crucial plant macronutrient for crop growth.The insufficient supply of nitrogen or phosphorus is a key limitation that restrict crop yield.In the past several decades,researchers consistently devoted self to breed many varieties with higher yield potential under more fertilizer application.The integrated application of fertilizer and high-yield variety has increased the crop production by forcefully.But there is a contradiction between large dosage of fertilizer usage and low fertilizer use efficiency of plant,which has brought enormous energy dissipation and cost of crop production, while the excessive fertilizer application also causes serious environment pollution. Understanding the genetic basis of crop nutrition absorption and utilization,is an important approach to resolve above mentioned problems.In this study we used two sets of chromosomal segment substitution lines(CSSLs) to analyze the genetic basis of rice responses to nitrogen and phosphorus stresses in the field experiment under three treatments of fertilizer application:normal(N),low nitrogen(NO) and low phosphorus(PO).The CSSLs were planted with augmented design and their plant height(PH),panicle length,panicle number and yield were measured at maturity stage. QTLs were identified related to the responses.The main results are as follows:1.Significant negative correlations between relative trait performance and its measurement under normal cultivated condition indicate a general trend that CSSLs in smaller plant size had higher relative performances.It also suggests that the CSSLs with smaller biomass often showed better tolerance to low nitrogen or low phosphorus conditions.However,there were many CSSLs showing higher values both in the relative trait index and the normal performances than that of the recurrent parent.2.In the CSSLs with 9311 genetic background,we detected 14 QTLs for plant height, 8 QTLs for panicle number and 18 QTLs for yield per plant.Qph-5b was a QTL for plant height with the highest(32.5%) variation explained and additive effect of 19.0 cm;All of the detected QTLs for panicle number showed negative effects,and explained phenotypic variations from -42.6%to -62.9%;The maximum phenotypic difference explained for yield per plant and the additive effect by Qyd-4c) is -88.1%and -9.6. In the CSSLs with Zhenshan97 genetic background,we detected 28,19 and 20 QTLs for plant height,panicle number and yield per plant,respectively.Qph-1d is one plant height QTL with the highest(68.9%) variation explained and its additive effect is 24.2cm, Qpn-5 for panicle number with the highest(58.9%) variation explained,Qyd-11a for yield per plant with the highest(137.9%) variation explained.3.The two sets of CSSLs have the common donor of Nipponbare within two different genetic backgrounds,one is 9311,another Zhenshan97.We detected a total of 58 and 93 QTLs in the two sets of population respectively.Most of the QTLs detected in the different two genetic backgrounds had various locations on the genome.Only 12 QTLs had the common locations such as the regions nearby markers RM472、RM211、RM7、RM411.The differences in QTLs number and location suggested that the different two genetic backgrounds might have very tremendous influence to the QTLs expression. Those QTLs repeatedly detected in different background had the characteristic of stability and authenticity,which is very important for MAS in breeding.4.For the CSSLs with 9311 genetic background,three QTLs(Qph-1c、Qph-5b and Qyd-4c) were detected repeatedly in the three kinds of treatments(N,NO and PO),for the CSSLs with Zhenshan97 genetic background,11 QTLs(such as Qph-5b、Qph-6、Qph-11a) were detected repeatedly in the different treatments.We suggest that these QTLs present more contribution to the traits growth and development.18 QTLs were detected under both NO and PO conditions(not detected under N condition),suggesting these stable QTLs across NO and PO treatments may have samiliar response to low nitrogen and low phosphorus stresses and more likely be common loci involving in nitrogen and phosphorus metabolism.The other most of the QTLs were only detected in either NO or PO treatment,suggesting that the loci are certainly more likely linked to the respective nitrogen or phosphorus pathway.The different QTLs detected under NO or PO treatments reflected diverse genetic basis of nitrogen and phosphorus responses.5.A total of 44 relative traits QTLs were detected in the two sets of CSSLs,of which 28 QTLs were common detected under the N,NO and PO treatments,other 16 QTLs were different from those detected under the N,NO and PO treatments.Thus,the genetic basis of the relative performances cannot simply be deduced as compared separate detection of QTLs under nitrogen and phosphorus treatments.For example,Qryd-3b is a QTL for relative yield which detected in the CSSLs of ZS97 genetic background.The material contained this QTL had a stronger tolerance to low phosphorus stress,however colocation QTLs were not detected under each of three fertilizer conditions.更多还原