水稻外观品质的数量性状基因位点分析

利用由98个家系组成的Nipponbare(粳)／Kasalath(秒)∥Nipponbare回交重组自交系(backcross inbred lines,BILs)群体(BC1F9)及其分子连锁图谱，采用复合区间作图的方法，在2个不同年份对粒长、粒宽、粒形、垩白率、垩白大小、垩白度和透明度等7个稻米外观品质性状的数量性状基因位点(Quantiative trait loci,QTL)进行了定位分析。共定位到33个四QTLs，单个性状QTL数目在4-7个之间，以垩白率最多，为7个；粒长和垩白大小次之，为5个；其他性状均为4个，表明该组合外观品质是由多基因控制的数量性状。单个QTL对性状变异解释率粒长为6．2％-15．2％，粒宽为8．3％-32．5％，长宽比为6．8％-19．8％，垩白率为6．4％-28．5％，垩白大小为6．1％-16．9％，垩白度为9．3％-17．2％，透明度为5．6％-25．2％．QTL在染色体上成集中分布的特点，第3染色体C1488-C563、第5染色体R830-R3166和R1436-R2289、第6染色体R2147-R2171均有3个以上的QTLs分布。比较2年的检测结果表明，外观品质性状的QTL定位都受环境影响，但不同性状受影响的程度差异很大。粒长和粒形的QTL定位受环境影响很小，垩白率、垩白大小和垩白度的QTL定位受环境影响很大。

Mapping Quantitative Trait Loci Underlying Appearance Quality of Rice Grains (Oryza sativa L.)

Ninety-eight backcross inbred lines (BILs) derived from a subspecific cross of Nipponbare (japonica)/Kasalath (indica)//Nipponbare and its genetic linkage map were used to identify quantitative trait locus (QTL) controlling rice appearance quality traits such as grain length (GL),grain width (GW),length-width ratio (LWR),percentage of grains with chalkiness (PGWC),square of chalky endosperm (SCE),degree of endosperm chalkiness (DEC) and grain endosperm transparency (GET) by composite interval mapping over two years.A total of 33 QTLs were identified to be significant in at least one year for seven traits and the number of QTL for each trait ranged from four to seven,showing that appearance quality of rice grains were controlled by multi-genes.The phenotypic variation explained by individual QTLs ranged from 6.2% to 15.2% for GL,8.3% to 32.5% for GW,6.8% to 19.8% for LWR,6.4% to 28.5 % for PGWC,6.1% to 16.9% for SCE,9.3% to 17.2% for DEC,and 5.6% to 25.2% for GET.The distribution of QTL were characterized by clustering with the intervals of C1488～C563 on chromosome 3、R830～R3166 and R1436～R2289 on chromosome 5,R2147～R2171 on chromosome 6 each harboring over 3 QTLs.The QTL-by-environment interactions were observed by comparing QTL mapping of the same population grown in 2 consecutive years,but were trait dependent.The QTL for GL and LWR were rather stable across years while that for PGWC,SCE and DEC were very sensitive to environments.