The genetic effects of the cooking quality traits amylose content (AC) and gel consistency (GC) of japonica rice were analyzed by using a genetic model including genotype environment (GE) interaction effects for quality traits of the endosperm in cereal crops. The results indicated that AC and GC of japonica rice were greatly controlled by the genetic main effects from endosperm, cytoplasm and maternal plant genes, but were also affected by GE interaction effects. The endosperm effects were most important among genetic main effects for the performance of AC and GC, while the cytoplasmic interaction effect or maternal interaction effects for AC or GC were more essential among GE interaction effects, respectively. Additive effects and cytoplasmic interaction effect were the main factors ontrolling the performance of AC, but GC was mainly affected by additive effects, additive interaction effects and cytoplasmic interaction effect. The endosperm general heritabilities were the largest ones among heritability components for AC and GC. A significant negative genotypic correlation was found between AC and GC. The genetic effects predicted for 13 parents showed that Liaojing 326 A and Hu 161 were the better parents for improving the rice cooking quality traits.

The relationships among potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn) contents in milled rice (Oryza stavia L.) of 274 genotypes and the relationships between these mineral element contents and other rice quality traits including 3 cooking quality traits, 17 amino acid contents, and protein content were investigated. The results showed that there were significant correlations among most of mineral element contents. Mg, Fe, and Mn contents were significantly correlated with most of the other mineral element contents, while Cu content had significantly negative associations with the K and Mg contents of rice. The relationships between mineral element contents and cooking quality traits showed that gel consistency (GC) was significantly correlated with K, Cu, and Mn contents of rice. Amylose content (AC) was significantly associated with K, Na, Mg, Cu, and Mn contents. The alkali spreading value (ASV) had closely positive relationships with Ca, Mg, and Mn contents. In addition, 8 mineral element contents had obvious correlations with different amino acid contents. Mg, Ca, and Zn contents were significantly correlated with most of the 17 amino acid contents, but Na content did not correlate with amino acid contents except aspartic acid of rice. Furthermore, significant associations were found between protein content and Na, Mg, Zn, Cu, or Mn content. Six principal components were extracted to explain 84.50% of the total variances and contained the information provided by the original 29 variables according to the principal component analysis.

The aim of this study was to evaluate the potential of near-infrared reflectance spectroscopy (NIRS) as a rapid method to estimate the cooking characteristics of rice. A total of 586 samples from rice breeding lines from 1999 to 2002, which had high variation for agronomy, location and year, were scanned by NIRS for calibration optimization by chemometric methods. Two subsets of 212 samples from one year and 400 samples from three years were employed to find suitable sample status for extending the NIRS utilities. There were three algorithms of PCA, PL1 and PL2, in which the first one was only based on the sample spectra variant and the remaining two based on the variant of both spectra and chemical characteristics to describe the relationship between any two neighboring samples. According to the results of calibration and validation by the three algorithms used, the suitable calibration samples could be chosen by the cutoff of neighborhood distance (NH) of 0.35, 0.4 and 0.45, respectively. For the cooking characteristics, the combination of SNV+D/4,4,1 was the best pretreatment and the accuracy models were obtained with low SECV and high 1 VRof amylose content (1.42% and 0.95%), gel consistency (9.49 and 0.76 mm) and alkali spread value (0.86 and 0.79 grade) . The models developed using brown rice and milled rice were superior to those using intact rice grains, but slightly poorer to those using their corresponding flour samples. Therefore, on-line monitoring of rice quality could be conducted in rice processing at milling stages. Due to the fewer sample mass destroyed, the brown rice (3 g) and brown rice flour (3g or 0.5g), by which the NIRS models were successfully developed for cooking characteristic analyses, could be introduced into quality evaluation of germplasm and intermediate lines selection in breeding projects.

Investigations to identify quantitative trait loci (QTLs) governing cooking quality traits including amylose content, gel consistency and elatinization temperature (expressed by the alkali spread value) were conducted using a set of 241 RIL populations derived from an elite hybrid cross of "Zhenshan 97" 9 "Minghui 63" and their reciprocal backcrosses BC1F1 and BC2F1 populations in two environments. QTLs and QTL 9 environment interactions were analyzed by using the genetic model with endosperm and maternal effects and environmental interaction effects on quantitative traits of seed in cereal crops. The results suggested that a total of seven QTLs were associated with cooking quality of rice, which were subsequently mapped to chromosomes 1, 4 and 6. Six of these QTLs were also found to have environmental interaction effects.

A dwarf mutant, dwarf 62 (d62), was isolated from rice cultivar 93-11 by mutagenesis with c-rays. Under normal growth conditions, the mutant had multiple abnormal phenotypes, such as dwarfism, wide and dark-green leaf blades, reduced tiller numbers, late and asynchronous heading, short roots, partial male sterility, etc. Genetic analysis indicated that the abnormal phenotypes were controlled by the recessive mutation of a single nuclear gene. Using molecular markers, the D62 gene was fine mapped in 131-kb region at the short arm of chromosome 6. Positional cloning of D62 gene revealed that it was the same locus as DLT/OsGRAS-32, which encodes a member of the GRAS family. In previous studies, the DLT/OsGRAS-32 is confirmed to play positive roles in brassinosteroid (BR) signaling. Sequence analysis showed that the d62 carried a 2-bp deletion in ORF region of D62 gene which led to a loss-of-function mutation. The function of D62 gene was confirmed by complementation experiment. RT-PCR analysis and promoter activity analysis showed that the D62 gene expressed in all tested tissues including roots, stems, leaves and panicles of rice plant. The d62 mutant exhibited decreased activity of a-amylase in endosperm and reduced content of endogenous GA1. The expression levels of gibberellin (GA) biosynthetic genes including OsCPS1,