利用7射线和EMs溶液诱变处理籼稻“93lJ”种子，经过M：筛选和M,重复鉴定，分别获得465份和210份（共675份）叶、茎、穗和根等性状变异的突变体，突变频率为5．62％。7射线诱变群体的变异范围要大于EMs诱变群体，突变频率也较高，但紫色叶鞘和叶片类病斑等少数突变类型只在EMS诱变群体中出现。新构建的突变体库将有助于进一步开展水稻功能基因的研究。

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.

Near-infrared reflectance spectroscopy was used to address the genetic potential for 990 rice lines for 26 quality traits. The predicted genotypic values for quality traits were calculated using the Mahalanobis distance method and used to measure the genetic similarities among rice varieties. To make the core collection, Manhalanobis distance was employed to calculate the genetic distance among the accessions, and the hierarchical clustering method was used to group the accessions, accompanied by sampling method under the pre-concerted sample proportion (i.e., the ratio of accessions in the core collection to those in the initial population). In this experiment, 24 core collections were developed by using eight hierarchical clustering methods, combined with random, preferred and deviation sampling at a sample proportion of 15% (i.e., 149 for the 15% core collection). These core collections were compared with others constructed at sample proportions of 10% and 20% (i.e., 99 for the 10% core and 198 for the 20% core, respectively). In addition, a trend at increasing sample proportion from 5% to 60% showed that core collection development could be achieved at a sample proportion range of 10–25%. Further results revealed that deviation sampling strategy in combination with the single linkage method retained the greatest degree of genetic diversity of the initial collection. The core collection developed using a sample size of 15% retained the highest degree of diversity, and was stable for all the cluster methods and, hence, the best in developing a core collection of rice quality traits.

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.

Using a newly developed mapping model with endosperm and maternal main effects and QTL environment interaction effects on quantitative quality traits of seed in cereal crops, the investigation of quantitative trait loci (QTLs) located on triploid endosperm and diploid maternal plant genomes for protein content and lysine content of rice grain under different environments was carried out with two backcross (BC1F1 and BC2F1) populations from a set of 241 recombinant inbred lines derived from an elite hybrid cross of Shanyou 63. The results showed a total of 18 QTLs to be associated with these two quality traits of rice, which were subsequently mapped on chromosomes 2, 3, 5, 6, 7, 10, 11 and 12. Three of these QTLs were also found havingQTL environment interaction effects. Therefore, the genetic main effects from QTLs located on chromosomes in endosperm and maternal plant genomes and their QTL environment interaction effects in different environments were all important for protein and lysine contents in rice. The influence of environmental factors on the expression of some QTLs located in different genetic systems could not be ignored for both nutrient quality traits.

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,