Glutinous Endosperm Research Articles

Estimation of pollen dispersal distance in Job's tears (Coix lacryma-jobi L.) by using red leaf sheath as a morphological marker.

Job's tears (Coix lacryma-jobi L.) is grown widely in Asian countries and a crop that can fertilize with own pollen and pistils. The grains are used not only for food but also for medicinal purposes. The grain of many cultivars contains glutinous endosperm; only grains with this glutinous endosperm are suitable for use as medicine in Japan. Many wild types have non-glutinous endosperm and can easily cross with cultivar under natural environmental conditions. Because the non-glutinous endosperm trait is dominant to that of glutinous endosperm, F1 seeds produced by crosses between a cultivar and a wild type have non-glutinous endosperm. To reduce the rate of unwanted crosses, we investigated the pollen dispersal distance by using a red leaf sheath as a morphological marker. When plants were cultivated in rows 70 cm apart, the crossing rate was about 25%-35%. As the distance increased, the crossing rate decreased at a rate that could be fitted to a power approximation in fields without intervening plants and to an exponential equation in fields with intervening plants. Our data could be used as guidelines for preventing unwanted crossing with wild types when growing cultivars.

Haplotype-based allele mining in the Japan-MAGIC rice population

Multi-parent advanced generation inter-cross (MAGIC) lines have broader genetic variation than bi-parental recombinant inbred lines. Genome-wide association study (GWAS) using high number of DNA polymorphisms such as single-nucleotide polymorphisms (SNPs) is a popular tool for allele mining in MAGIC populations, in which the associations of phenotypes with SNPs are investigated; however, the effects of haplotypes from multiple founders on phenotypes are not considered. Here, we describe an improved method of allele mining using the newly developed Japan-MAGIC (JAM) population, which is derived from eight high-yielding rice cultivars in Japan. To obtain information on the haplotypes in the JAM lines, we predicted the haplotype blocks in the whole chromosomes using 16,345 SNPs identified via genotyping-by-sequencing analysis. Using haplotype-based GWAS, we clearly detected the loci controlling the glutinous endosperm and culm length traits. Information on the alleles of the eight founders, which was based on the effects of mutations revealed by the analysis of next-generation sequencing data, was used to narrow down the candidate genes and reveal the associations between alleles and phenotypes. The haplotype-based allele mining (HAM) proposed in this study is a promising approach to the detection of allelic variation in genes controlling agronomic traits in MAGIC populations.

Variation in Grain Quality of Upland Rice from Luang Prabang Province, Lao PDR

Luang Prabang Province is located within the area recognized as the center of rice (Oryza sativa L.) diversity in Lao PDR. This study reported on grain quality characteristics of 60 upland rice seed samples sharing 49 variety names collected from 6 villages in Luang Prabang in 2015. Most of the samples has non-pigmented pericarp, while red pericarp was found in four samples and purple in five samples. Almost all of the samples were of large grain type, with glutinous endosperm in 70% and non-glutinous endosperm in 30%. The brown (unpolished) rice was found with a wide range of grain nutritional quality, including protein (9.2% ± 0.9%), Fe (15.9 ± 6.9 mg/kg), Zn (19.6 ± 2.1 mg/kg), anthocyanin (0.774 ± 0.880 mg/g), and anti-oxidative capacity (2.071 ± 1.373 mg/g). The varieties sharing similar names had similar morphological characteristics but varied in nutritional concentration, with required confirmation in genetic variation analysis. This study found that some rice varieties with high grain quality may benefit the farmers directly or could be used in varietal improvement programs.

Development of one corn ear and verification the three laws of inheritance

A new corn was developed as a lab material to verify the three Laws of Inheritance on only one F2 ear with correct segregation ratios of kernel traits. In order to investigate the three Inheritance Laws simultaneously with one ear, the sweet endosperm (Sn1), kernel color (C1) and the glutinous endosperm (Wx) were chosen as the original phenotypes. Gene Sn1sn1 is located on chromosome four, genes C(1c1) and Wxwx are located on chromosome nine. After several generations of continuous self-pollination and test crossing, direct crossing and back crossing, with strict selections, the homozygous parents were obtained. With different combinations of homozygous parents, different hybrids were developed. The segregation ratios of each phenotype on the same F2 ear are compared to the theoretical segregation ratios according to the corn gene exchange and gamete types and quantities produced through meiosis. The results showed three ratios of 3:1, two ratios of 9:3:3:1, and one ratio of linkage and exchange, with all the chi-square values smaller than the permitted ones. This means that only one ear of this new hybrid corn can be used as a new teaching aid to examine and verify the three Laws of Inheritance.

Molecular characterization of mutations induced by gamma irradiation in rice

In order to analyze mutations induced by gamma irradiation in higher plants, we irradiated rice with gamma rays and screened for mutations expressing phenotypes of glutinous endosperm (wx), chlorophyll b deficiency, endosperm protein deficiency, gibberellin-related dwarfism, and shortened plastochron-in order to clarify types of mutations. Nucleotide sequence analysis showed that the most frequent mutation induced by gamma rays was deletion, particularly small deletion. Of the 24 mutations, 15 were small deletions (1-16 bp), four were large deletions (9.4-129.7 kbp), three were single-base substitutions, and two were inversions. Deletions 100 bp-8 kbp in length were not found, suggesting that gamma irradiation is unlikely to induce deletions of 100 bp to 8 kbp but is more likely to induce deletions between 1 and several ten bp or those of around 10 kbp or more. Based on the results, reverse genetics applications may be possible for gamma irradiation-induced deletions in rice by mismatch cleavage analysis used in Targeting Induced Local Lesions IN Genomes (TILLING) to detect small deletions and base substitutions or by using array comparative genomic hybridization (aCGH) to detect large deletions.

Gene flow from cultivated rice (Oryza sativa L.) to wild Oryza species (O. rufipogon Griff. and O. nivara Sharma and Shastry) on the Vientiane plain of Laos

Although Asian cultivated rice (Oryza sativa) and its annual (O. nivara) and perennial (O. rufipogon) wild relatives can freely exchange genes under experimental conditions, little is known about gene flow from the cultivated to these two wild species in natural habitats. The area of study was the Vientiane plain of Laos, at the center of the glutinous rice zone. The objectives of this study were (1) to determine the extent of hybridization between rice and its close wild relatives over a large area on the basis of the O. sativa specific traits glutinous endosperm, colorless apiculus and white pericarp; (2) to evaluate the genetic variation in the hybrid plants based on 13 quantitative traits using principal component analysis. Out of 1576 individual plant samples analyzed two hybrid groups were recognized. One hybrid group consisted of O. rufipogon–O. sativa hybrids and represented 10% of wild individual plants analyzed. The other hybrid group was O. nivara–O. sativa hybrids that represented 14% of wild individuals analyzed. These hybrid groups are distinct based on principal component analysis – this is due to both spatial isolation (> 100 m) and reproductive isolation (i.e. differential flowering time). The results indicate that two kinds of gene flow, between (a) O. sativa and O. rufipogon and (b) O. sativa and O. nivara, are occurring throughout the Vientiane plain of Laos.

Geographical distribution of genes causing hybrid breakdown in varietal crosses of Asian cultivated rice

In a backcrossing program to introduce the wx (glutinous endosperm) gene from a Thai upland rice cultivar, Col.No.15, to a Japanese cultivar, Sasanishiki, of Asian cultivated rice, Oryza sativa L., weak plants were observed in the BC1F1 generation. These weak plants were characterized by poor growth and discoloration at the tillering stage, though they were completely fertile. Hybrid breakdown, which is defined as hybrid weakness and sterility detected in the F2 and later inbred generations of varietal crosses, is controlled by a pair of recessive genes, hwd1 and hwd2, at unlinked loci. Two dominant genes at either the same or different loci, Hwd1/Hwd1 hwd2/hwd2, hwd1/hwd1 Hwd2/Hwd2 or Hwd1/hwd1 Hwd2/hwd2, are needed for normal growth. Using tester lines homozygous for a pair of recessive genes selected in the BC1F3 generation, the genotypes for hybrid breakdown of 100 Asian rice cultivars were determined based on the phenotype of F1 plants. Clinal variation for hybrid breakdown was observed. Cultivars with two dominant alleles at either hwd1 or hwd2 locus, were mainly found in insular Asia (Japan, Philippines and Indonesia), while the frequency of cultivars with four dominant alleles was more common in cultivars from continental Asia. Roles of hybrid breakdown in genetic differentiation of Asian cultivated rice are discussed.

Glutinous (waxy) endosperm starch mutant of Triticum monococcum L.

Cultivars or mutant lines which contain glutinous endosperm starch have been developed in seven crops, including rice, maize, barley, etc. However, reports on Triticum species with glutinous endosperm are not available. Attempts were made to induce the mutation of endosperm glutinousness in Triticum monococcum L. by treatment with EMS. Four hundred seeds of T. Inonococcum were pre-soaked for 20h and treated with 0.4% (v/v) EMS for 24h at room temperataure. Germination percentage was 42.0%After transplanting of the M1 seedlings to a field, 99M1 plants died partly due to late transplanting and severe winter weather conditions. However, 2, 016 M2 seeds were harvested from the fertile 59M1 plants which survived. By staining the endosperm starch of the distal part of the seeds with a KI-I2 solution, six out of 2, 016 seeds showed a red brown color, which is the typical reaction of glutinous endosperm starch to KI-I2. Consequently, these six M2 seeds were considered to be glutinous endosperm mutants. The appearance of these seeds was not different from that of the seeds of normal T. monococcum. Two M2 seeds were also obtained, in which the endosperm starch showed a reddish purple color rather than the typical purple color of non-glutinous starch. The present results indicate that glutinous endosperm mutants can be obtained in Triticum species.

Inheritance and expression of reduced culm number character in rice.

A mutant with a reduced culm number was found in M2 population of AC-3 (a strain regenerated from A-5 Akamuro by anther culture) after gamma-ray irradiation of dry seeds. In F2 population of the crossing between the mutant line, N-133 and the original strain, A-5, it was demonstrated that a single recessive gene, rcn is responslble for the reduced culm number type. A pleiotropic effect showing dwarfness was expressed although the seed fertility was unaffected. In the linkage analysis, it was found that rcn was linked with the genes belonging to the first linkage group such as wx (glutinous endosperm) and C (Chromogen for anthocyanin) in the order of wx-C-rcn. In addition, rcn was epistatic to the dwarf genes, d-2 (ebisu dwarf), d-3, d-4, d-5 (triplicate genes for bunketsu waito) and d-10 (toyohikari-bunwai). As for the relation with d-6 (ebisumochi dwarf), a non-parental dwarf type with a reduced culm number and shorter lower (below the second) internodes occurred as a double recessive genotype. The character expression of the mutant gene, rcn was remarkably affected. by the temperature conditlons during the growth period. Plant height and culm number of the mutant recovered to nearly normal when grown in a plastic house with the application of nitrogen. Since the plant height and culm number were retarded by the treatment with cold water (15°C), it was demonstrated that the gene expression was conditioned by the low temperature.

The transfer of a gene for glutinous endosperm to Oryza glaberrima Steud. From a japonica variety of O. sativa L.

In common rice, Oryza sativa L. (n=12), the gene Am for ‘non-glutinous’ is dominant over the gene am for ‘glutinous’. In African rice, O. glaberrima Steud. (n=12), no spontaneous glutinous strain has been found, but recently a glutinous strain of glaberrima was induced by EMS-treatment.

Studies on linkage relations of genes controlling disease and insect resistance and nature of endosperm in rice

Five hundred F3 lines derived from the cross TN1/IR2061-464-6 were examined for the nature of endosperm and resistance to bacterial blight, brown planthopper, and grassy stunt. TN1 has non-glutinous endosperm and is susceptible to bacterial blight, grassy stunt, and brown planthopper. IR2061-464-6 has a glutinous endosperm and is homozygous resistant to bacterial blight, grassy stunt, and brown planthopper. The F3 data fit the 1:2:1 ratio expected for monogenic control of each trait. A two-way classification for all the traits indicated that these four traits are inherited independently. Thus, it should be possible to recombine these four traits in various combinations in rice varieties.

Studies on Inheritance of Resistance of Rice Varieties to Blast : 2. Genetic relationship between the blast resistance and other characters in the rice varieties, Reishiko and Sekiyama 2

F2 and F3 populations of hybrid between a Chinese variety, Reishiko, and a Japanese variety, Sekiyama 2, were analyzed. Reishiko has a dominant gene (Pi-k) controlling resistance to strains of the blast fungus. Ken 54-20 and P-2b, a dominant gene for colour of palea and lemma, glutinous endosperm gene wx, and a recessive gene for yellow seedling. Sekiyama 2 has a dominant gene (Pi-i) controlling resistance to strains of the blast fungus, P-2b and Ina 72, a dominant gene different trom one of Reishiko for colotlr of palea and lemma, non-glutinous endosperm gene Wx, and a recessive gene, different from one of Reishiko and functioning complementally with one of Reishiko, for yellow seedling. There are no linkage relationships among these genes found in both the varieties except of a linkage (26.9±8.5%) between gene for colour of palea and lemma, and gene for glutinous endosperm. This gene for colour of palea and lemma in Reishiko was considered to be same as C found in earlier studies.

Fundamental studies on rice breeding through hybridization between Japanese and foreign varieties. : XIII.On the C-gl linkage relation in the progeny of the cross, Surjamkhi×Norin No.1

The authors reported already that duplication and deficiency of C-locus which bore the gene responsible for the production of chromogen in the rice plant occurred in F2 of the cross, SurjamkhixNorin N0.1, and that it might be due to cryptic translo-cation or inversion (recombination value : ca. 50 per cent) of the gene locus (MIZUSHIMA and KONDO, 1959, '60). In the present paper reports the result of investigation of segregation in respect to C and gl genes in F2 of the cross, F5 (Surjamkhi x Norin No. 1) XHokkaimochi No. 1. The F5 plants used consisted of five having nonglutinous endosperm and colored glurme apiculus, and showed the effects of the dominant C- and glgene. One of them, however, was confirmed previously to have doubled C-loci, of genotype CBCB1APgl+ (KONDO and MIZUSHIMA, 1964 b). A is the gene which converts the chromogen into anthocyanin and P distributes anthocyanin to the site of apiculus in glume. Hokkaimochi No. I has glutinous endosperm and colorless apiculus whose genotype has been identified as C+A+pgl. In F2 CBCB1APgl+ X Hokkaimochi No. I a clear linkage relationship was observed between C- and gl-gene. However, it was difficult to determine which of the two C-genes, CB and CB1, was linked to gl. In the other three crosses the C-gl linkage was also confirmed and the recombination value was almost the same as reported by other workers (CHAO, 1928 ; NAGAO, 1951 ; JODON, 1957). From the linkage between C and gl observed in the present experiment we consider that duplication and deficiency of C-locus in the hybrids reported is not due to its cryptic translocation. However, the possibility of change in position of C-locus from one side of gl-locus to the other by inversion, keeping a linkage relationship between the two, still remains. This was discussed briefly from the tetrasomic segregation of C-gene already observed in the hybrids one of whose parent was Surjamkhi (KONDO and MIZUSHIIMA, 1964a) we concluded that the cause of duplication and deficiency is more probably atributable to a peculiar modes of conjugation of chromosomes bearing C-locus than tonversion as already suggested previously (KONDO and MIZUSHIMA, 1964 b).

Fundamental studies on rice breeding through hybridization between Japanese and foreign varieties. III, Anomalous modes of segregation of glutinous character observed in hybrids between varieties of remote origin

Summary Some anomalous modes of segregation in respect to giutinous character in pollens and in endosperms of seeds born on F1 hybrids between rice varieties of remote origin are described. Glutinous ×non-glutinous F1 hybrids from 72 different parental combinations among 25 varieties including 9 glutinous and 16 nonglutinlous ones were investigated. Eight of the 9 giutinous varieties used are of Japanese origin and one is of South American origin, all of these belonging to so-called Japonica group. Six of the 16 non-glutinous varieties belong also to Japonica, of which 5 are of Japanese origin and one, Sen-sho, is native to China, having been intoduced into Japan some 70 years ago. The other lO ones consist of 5 Indian, I Viet Namese, 1 Hawaiian and 3 Chinese varieties and they belong to so-called 1lrdica group (Table 1). In all of the F1's obtained among Japaneese varieties segregntion of glutinous character in both pollens and endosperms took place normally, i. e., the ratio non-giutinous vs. glutinous was 1 : 1 in pollens and 3 : 1 in endosperms. In some hybrids between Japanese and Indian varieties there occured a remarkable deviation from the normal ratio, presenting a significant decrease in the number of glutinous endosperm, though the segregation in their pollens was normal. In the two sets of hybrids in which other foreign varieties than Indian ones partook as a parent there was observed a significant decrease in the number of non-glutinous pollens. The segregntion ratio in endosperns was, however, normal in most of them. Sen-sho was found to behave in a complex manner.

Studies on Tetraploid Rice

1. In tetraploid hybrids between distantly related varieties of cultivated rice, such as between the Continental and Insular groups, the F1 plants generally showed relatively high fertility. However, plants with different fertilities were produced after the F2 due to segregation and the mean fertilities tended to go down with the repetition of generations. Plants showing vigorous growth tended to have high fertility.2. In the tetraploid hybrids between distant varieties, F2 segregation ratios so far observed for several monogenic characters (phenol reaction, apiculus pigmentation, glutinous endosperm and seed coat coloration) all agreed with the autotetraploid ratios 35:1 or 20.8:1, based on the assumption of random pairing of homologous chromosomes or chromatids.3. The F2 genotypic ratio for glutinous endosperm showed a significant deviation from the expected ratio: glutinous homozygotes and simplex heterozygotes were deficient. This deviation was found to be due, not to selective pairing of chromosomes, but to a certation in favor of non-glutinous pollen, in the same manner as in diploid hybrids.4. It was concluded that tetraploid hybrids between distant varieties of cultivated rice have no amphidiploid-like nature, and that the variation in cultivated rice is mainly due to genic changes.

Phylogene.tic differentiation of the cultivated rice., xi., Change of gene frequeney in hybrid populations of rice.

1. In rice, when an i, ntervarietal hybrid in pro. pagated without selectijon, it is geherally found that the frequencies of genes charige with the repetition of inbreeding generations. The freduehcy of recessive hompzygoteS in successive generations of hybrids was investigated for such genes as C : c for, apiculus pigmentatiori, + : gl for glu-tinous endosperm. Rc :, rc for seed coat coloration, and Ph : ph for phenol reaction. Ih. hybrids between . varieties of the "Continental group" and the "Insular Group", genes of the formet generally tended to increase against thpse of the latter.