Correlations And QTL Mapping For Eating Quality Characters In Japonica Rice

Rice is an important crop cereal, and its eating quality is concerned more and more. To evaluate the eating quality impersonally and provide the information for the rice breeding is the problem needed being resolved imminently. In this paper, the relationship between the tested value(the synthetic value of taste analyzer) and taste synthetic evaluation for 100 japonica varieties, relationship between eating quality and 31 agronomic characters in 30 combinations derived from 6 new BT-type japonica sterile lines and 5 restorer lines were studied; The F₂ population of Wuyujing 3/Aichi 106 were used for inheritance of the RVA profile. The recombinant inbred line(RIL) population derived from Nikken 2/Milyang 23 and its genetic linkage map were used to map the quantitative trait loci (QTL) controlling RVA profiles. The results were summed as bellow:The tested value was positively correlated with taste synthetic evaluation by eating quality factors, the correlation coefficient (r) was 0.768, and the taste analyzer was an accurate tool for rice eating quality evaluation.There was a significant positive relationship between tested value and plant height, panicle neck length while a negative relation between tested value and width of panicle neck, tiller angle, width of first leaf, width of second leaf, width of third leaf, first leaf base angle, first leaf angle. The path analysis of the above 9 characters to tested value indicated that plant height, width of panicle neck and the first leaf had highly significant direct effects to tested value. The eating quality would be good for such combination with middle plant height, thin panicle neck, more panicle, high seed setting, small base angle, angle and narrow leaf blade of first leaf.The rice starch viscosity characteristics, also termed the RVA profile, is a paste curve of rice flour when the paste is subjected to a standard temperature, programmed heat-hold-cool protocol. The RVA profile which could be expressed by eight characters: PKV(peak viscosity), HPV(hot paste viscosity), CPV(cool paste viscosity), BDV (breakdown viscosity), CSV(consistency viscosity), SBV(setback viscosity), PeT(peak time) and PaT(pasting temperature). The RVA profile has been proved useful for the evaluation of eating and cooking quality in rice breeding program. So the F₂ populations of Wuyujing 3/ Aichi 106 were used for inheritance analysis of the RVA profile. The results indicated that: PKV was a typical quantitative character; HPV, CPV, SBV, BDV, CSV might be controlled by a major gene and several minor genes; but PeT controlled by two major genes and several minor genes. In order to understand the genetic basis of the paste viscosity characteristics, the recombinant inbred line populations derived from Nikken 2/Milyang 23 and its genetic linkage map was used to map the QTLs controlling RVA profiles in 2005 and 2006, The results showed that, a total of 35 QTLs distributed on the first, second, third, fourth, sixth, seventh, eighth chromosomes were detected in 2005 and 2006; Eight QTLs were found in both two years in which the qHPV6, qCPV6, qCSV6, qSBV6, qBDV6 were located on chromosome 6, while qHPV2, qCSV2, qCPV2 were located on chromosome 2.