【作者】 周树峰；

【导师】 李晚忱；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2003， 硕士

【摘要】 干旱是影响我国玉米生产的主要限制因素之一。2001年，我国发生干旱面积约为2300多万公顷。玉米是旱地作物中需水量大，对水分胁迫很敏感的作物之一，干旱严重影响到玉米产量。在我国西南玉米生态区大部分玉米种植在无灌溉条件的旱土坡地，在苗期和灌浆期发生的季节性干旱对玉米生产遭成严重损失。 防御干旱，提高玉米生产力需从两方面着手，一是改良水利设施，使之满足玉米生长所需；二是改良作物自身，使之适应干旱而获得稳产。通过鉴定、筛选耐旱玉米种质资源，培育耐旱玉米品种是提高我国干旱地区玉米生产力的一条费省效宏措施。 本试验采用控制灌水措施，在土壤含水量略高于耐旱自交系萎蔫系数的干旱条件下，鉴定了我国常用以及新近选育的57个玉米自交系的耐旱性，并调查了耐旱性不同的12个玉米自交系与耐旱性有关的15个生长发育和生理生化指标，根据其与正常灌水对照的差异计算耐旱系数，并与籽粒产量耐旱系数进行了多元回归分析。结果表明，玉米自交系间存在着较大的耐旱性差异，其中雌雄花期间隔和单株籽粒产量的耐旱系数，变异范围在0.01-0.93和0.05-0.81之间。耐旱性有如此大的变异范围，正是培育耐旱玉米品种的潜力所在。 在耐旱性鉴定结果的基础上，选择耐旱性差异较大的两对自交系，组配其P1、P2、F1、F2、B1、B2六个世代群体，又选耐旱性不同的11个自交系，按Griffing(1956)完全双列杂交方法4，组配55个F1杂交组合。调查与耐旱性相关显著的耐旱性指标并计算其耐旱系数，进行基因效应和遗传参数估计。 1．耐旱性强弱的鉴定结果 57个自交系中只有81565的籽粒产量耐旱系数在0.8以上，属于强耐旱性自交系；N87-1、R09等7个自交系的耐旱系数在0.61至0.80之间，属于耐旱性较强的自交系；P3245-4、掖52106等36个自交系的耐旱性中等，耐旱系数在0.41至0.60之间；L30、中451等9个自交系的耐旱性较弱，耐旱系数在0.21至0.40；而21-ES、200B、丹340和9526，则为不耐旱自交系，耐旱系数低于0.20。 2．苗期耐旱性鉴定指标的筛选 通过对苗期调查的6个性状的耐旱系数与单株籽粒产量耐旱系数的多元回归分析，以出苗率和生物学产量对玉米耐旱性的贡献达极显著水平。说明干旱条件下出苗率高、生物学产量积累量大的品种耐旱性强，反之，耐早性弱。 3.成株期耐早指标的筛选 通过对9个性状的耐旱系数与单株籽粒产量耐早系数的多元回归分析，以株高(xv)、雌雄花期间隔(龙;)、出叶速度(xlZ)、根重(xl3)和脯氨酸含量(xls)的耐旱系数对单株籽粒产量耐早系数(为)的影响达显著或极显著水平。说明这些性状可以作为玉米成株期耐早性的鉴定指标。 4.苗期耐早性与成株期耐早性的相关 出苗率耐早系数与生物学产量耐早系数的乘积(抓二xlx溉)与单株籽粒产量耐旱系数(劝的简单相关系数二0.840*.，达极显著水平，说明苗期耐早性的强弱与成株期的耐早性有显著相关性，可以通过苗期耐旱性鉴定来预测成株期的耐早性。 5.脯氮酸含量的变化 通过对不同时期脯氨酸含量的测定发现，在幼苗期，千早条件下多数自交系脯氨酸含量比对照增高，但规律性不强，与籽粒产量耐早系数相关不显著。随着干早的持续影响和植株的长成，干早条件下多数自交系脯氨酸含量比对照降低。但是，耐早性强的自交系脯氨酸含量降低幅度小于耐早性弱的自交系，且与籽粒产量耐早系数的相关性达极显著水平。 6.世代群体估算的各耐早指标基因效应 通过对杂交组合81565(强耐早)x9526(不耐早)和R09(较强耐早)x丹340 (不耐旱)六个世代群体7个耐早指标的研究，表明玉米耐旱性的遗传是一个较为复杂的性状，不同杂交组合同一性状均符合不同的遗传模型，但在两个组合的7个耐旱指标中，显性效应值均大于加性效应值，显性比加性更重要。 7.双列杂交估算的相关遗传参数 通过对n个亲本组配的55个双列杂交组合中12个性状耐早系数与单株产量耐旱系数所进行的多元回归分析表明仅有穗长、穗粒数、百粒重的耐旱系数与单株产量的耐旱系数达极显著水平，且上述4个耐早指标的遗传效应均以显性效应为主，显性方差大于加性方差，说明在耐旱性品种选育方面应注意杂种优势的利用。在所研究的耐旱性相关指标中除单株产量的狭义遗传力较高为29.28%外，其余各指标的遗传力均不高，其中百粒重的狭义遗传力仅为7.59%。更多还原

【Abstract】 Drought is one of the main limited factors in maize production in China . The drought areas were more than 2300 ten thousand ha. in the year 2001, and maize is a kind of crop that needs much water, and is sensitive to water stressing among dry land crops , so drought has a greatly effect on maize yield. In Soirfhwest maize ecological region, one of the main maize production regions in China, most of the maize fields distribute on mountain and hill slopes with barren soil and rain-fed condition. Seasonal drought that often occurs during seedling emergence and milking stages causes significant loss of maize yield.There are two ways for resisting and defending drought and raising maize yield .One is to improve water equipment ,whose aim is to meet the need of plant living ;the other one is to develop the drought tolerance of maize. Comparing the two ways above, the later is a better one for breeding drought tolerance maize variety through identifying and screening maize germplasm materials of drought tolerance.The lowest soil moisture, the wilting coefficient of the sandy loam soil in the experiment field, under which drought tolerance inbred lines could germinate and grow was screened through pot experiment by controlling water in a plastic roof to prevent rainfall. High-quality seeds of the 57 experiment inbred lines popularized in China or newly bred were selected by germination test and sown. Soil moisture was controlled a little higher than wilting coefficient, the drought tolerance of 57 inbred lines was identified, and 15 indexes related to drought tolerance about growing and physiologic and biochemistry of 12 inbred lines were investigated. Drought tolerance coefficients were calculated, according to difference of drought compared with non-drought, and a multiple regression analysis was made with drought tolerance coefficient of per plant kernel yield as dependent variable.The result displayed there was a wide difference of drought tolerance in maize inbred lines. The coefficients of drought tolerance of Anthering and Silking interval and per plant kernel yield had a variance of 0.01~0.93 and 0.05~0.81. Such a big variance range of droughttolerance was just a potential for breeding drought tolerance variety.4 inbred lines with significant difference of drought tolerance were selected based upon the drought tolerance identification result of 57 inbred lines to make 6 generation group of PK P2> FK F2^ BK B2, in the same time 11 inbred lines with different drought tolerance were chosen to make 55 crosses according to complete diallel crosses of Griffing method 4. All the indexes with significant correlation to drought tolerance were investigated and transformed to drought tolerance coefficients to carry out the estimation of gene effect value and the related genetic parameters. All the experimental results are summarized below.1. Identification result of drought tolerance on 57 inbred linesThe drought tolerance of the 57 inbred lines could be divided into five levels according to their drought tolerant coefficients of per plant kernel yield. Level I: the strongest drought tolerance whose drought tolerance coefficients were over 0.8 only including 81565; Level II: the stronger drought tolerance whose drought tolerance coefficients were 0.61~ 0.80 including N87-1, R09 and 5 others; Level III :the middle drought tolerance whose drought tolerant coefficients were 0.61~0.80 including P3245-4, Ye52106 and 34 others; Level IV: weaker drought tolerance whose drought tolerance coefficients were 0.21~0.40 including L30> Zhong451 and 7 others; Level V: the weakest drought tolerance whose drought tolerance coefficients were under 0.20 including 21-ESx 200B, Dan340 and 9526.2. Screening of drought tolerance indexes identified during seedling stageThe multiple regression analysis of drought tolerances on 6 indexes identified during seedling stage with per plant kernel yield as dependent variable showed that the contributions of emergence rate and biomass to maize drought tolerance were very significa更多还原