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.

Following the sequencing of rice genome, the functional analysis of unidentified genes is gaining wide importance. For these, mutant isolation is one of the effective ways to isolate and clone the target genes and analyze their functions. For finding the various mutants in the same genetic background, seeds of Oryza sativa cv. Nipponbare were treated with ethyl methane sulphonate (EMS). A total of 1056 mutants for five categories were screened in M2 generation with the seedling frequency of 26.29‰ at three-leaf stage, but only 264 mutants were verified in M3 generation with a frequency of 6.57‰. Among the mutants verified in M3 generation, the frequency of leaf mutation was highest (2.22‰), followed by seedling height (1.74‰) and abiotic stress tolerance mutant (1.47‰). Nineteen characteristic mutations, including a big group of abiotic stress tolerant mutants such as herbicide resistant, salt tolerance and drought tolerance were identified at this stage. By observation of rice growth characteristics at different developmental stages, another 220 mutants have been isolated and verified in the M3 generation with the mutant frequency of 53.9‰ covering about 28 mutant taits. Among those identified, the highest frequency were obtained for appearance of brown rice mutant with 18.37‰ followed by panicle mutant with 13.47‰ and grain mutants with 9.06‰, respectively. All the mutants screened above were suitable for gene function analysis and for utilization in agronomy.

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,

The analysis of temporal patterns of genetic effects for thousand-seed weight (TSW) and oil content (OC) in rapeseed was conducted at five different seed development times using unconditional and conditional genetic models for diploid seed quantitative traits. Phenotypic means among generations and seed development times in 2 different years revealed considerable variation for both TSW and OC. The expression of genes from diploid embryo, cytoplasmic and maternal plant genetic systems were all found to be important for the F1 generation, with maternal effects playing a more prominent role for both traits at most times. The conditional analysis indicated that the stage-specific gene expression from the maternal plant was influenced by environment. Higher magnitudes of additive and cytoplasmic effects were observed for both traits. Narrow-sense heritability was high for both traits at all developmental times with maternal heritability being more prominent at most times. Genetic correlations between TSW and OC were mostly negative over developmental times.

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.