No abstract

Genotypic variation and nutritional quality of rice has been established, but environmental effects on the genotype are unknown. This study determines how nutritional quality, such as pericarp colour and antioxidant capacity, of purple rice can vary when grown under different environments. Nine purple rice genotypes and Khao Dok Mali 105 (KDML105, a non-pigmented rice) were grown at 2 different altitudes (330 m and 800 m above mean sea level, designated lowland and highland, respectively) at Chiang Mai, Thailand. Grain yield, Zn, anthocyanin concentration, and anti-oxidative capacity of the rice genotypes varied significantly in direction and magnitude. Grain Zn was higher in the lowland, but with differences between altitudes ranging from 16% to 50% among the purple rice genotypes, while non-pigmented KDML105 was among the lowest in grain Zn concentration at both altitudes. Some genotypes produce rice with more intense pigmentation and higher concentration of monomeric anthocyanin in the highland, some did so in the lowland, while no altitude effects were seen in others. Antioxidant capacity (Trolox equivalent) of the rice increased with increasing concentration of anthocyanin (R 2 = 0.72, p < 0.01), and varied in a multiple regression with anthocyanin and Zn concentration (R 2 = 0.75, p < 0.01). The effect of altitude on variation of grain nutritional quality among purple rice genotypes between the two growing conditions should be taken into consideration in efforts to enhance valuable nutrients in agronomic and breeding programmes.

This experiment examined variation of iron (Fe) concentration in grain of local Thai rice varieties from Huai Tee Cha village, in northern Thailand. Seeds of 17 named varieties were collected from farmers in 66 accessions. Brown rice from each accession was stained individually with Perls' Prussian blue, with IR68144 (high grain Fe) and KDML105 (low grain Fe) as checks. A wide range of grain Fe contents were found among different varieties, different seed lots with the same name and within individual accessions, notably BB, BGU and BK. The Fe concentrations in these varieties were confirmed by chemical analysis. Two accessions of each variety with most intense staining and highest average concentration of grain Fe were selected, and 20-40 seeds from each were sown for subsequent progeny testing. There was morphological variation between plants in 5 out of 6 accessions in characteristics such as pigmentation of the apiculus, pericarp and seed coat, while the sixth was externally uniform.Analysis for Fe concentration in seeds of individual lines found that the highest Fe lines were 40% to 50% higher than the lowest Fe lines. This range of grain Fe was found in all six accessions that were progeny tested, including BGU5 which was externally uniform in appearance (H 0 = 0). We have shown that variation in grain Fe concentration in local Thai rice may be found between different seed lots bearing the same name and within individual seed lot as well as between varieties. This level of genetic variation may need to be considered when assessing for traits such as grain Fe for breeding programs.

The seed of rice (Oryza sativa L.) from the highlands of northern Thailand, which is located within the species' centre of diversity, constitutes some of the world's last local rice germplasm still retained on-farm, provides local farmers and communities with a readily accessible resource, and is a source of value-adding traits for rice breeding. This paper reports on the germplasm represented by 281 seed samples collected in 2013 from an area of the highlands between latitudes 17.76°N to 20.18°N and longitudes 97.76°E to 100.48°E. The samples were provided by farmers belonging to 10 ethnicities, in number that closely correlated with the groups' share of the highland population (r = 0.84; P < 0.01). Compared with the slender grain rice of the lowlands, the highland germplasm was distinctive in its grain shape, and classed as large grain type in the husk, and medium grain type as de-husked, brown rice. The rice, which was predominantly of non-glutinous grain type and grown mainly as upland rice, had generally higher iron concentrations than rice in the lowlands; thus demonstrating how an on-farm rice germplasm may directly benefit local farmers and communities who consume the rice they grow. In addition, potential value-adding traits were identified in varieties and seed samples with the highest zinc density and novel rice with pigmented pericarp and high anti-oxidative capacity.

This study examined variation in seed zinc (Zn) in a local upland rice germplasm that may affect adaptation in a system of slash-and-burn. Individual seed Zn in farmers' seed lots of local upland rice varieties from a slash-and-burn system was evaluated by staining with dithizone (DTZ). Concentration of Zn in the farmers' seed lots and their single-seed descent genotypes grown at Chiang Mai University was determined by chemical analysis. The DTZ staining of individual seeds in most of the farmers' seed lots covered the intensity of standards that ranged from 19 mg Zn/kg (RD21) to 31 (Nam Roo) mg Zn/kg. Zinc content by chemical analysis was closely correlated with the weighted-average staining for each seed lot. Almost all of the single-seed descent genotypes had higher seed Zn than RD21; two-thirds were higher than Nam Roo. The variation within seed lots detected by DTZ staining was confirmed by seed Zn in the single-seed descent genotypes. Evolutionary adaptation to soil with limited Zn, exacerbated by alkalinity of the ash from slash-and-burn, is made possible by variation in seed Zn among individuals growing together in the same field, and benefits the eaters with Zn-enriched seed.

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Local upland rice germplasm is an invaluable resource for farmers who grow rice on acidic soils without flooding that benefits wetland rice. In this study, we evaluated the adaptation to soil acidity in common local upland rice varieties from an area with acidic soil in Thailand. Tolerance to hydrogen and aluminium (Al) toxicity was determined by measuring root growth, plant dry weight and phosphorus (P) uptake in aerated solution culture without the supplementation of Al (0 mg/l) at pH 7 and 4 and with the supplementation of 10, 20 and 30 mg Al/l at pH 4. The root growth of upland rice plants grown from farmers' seed was depressed less by Al than that of common wetland rice varieties. Pure-line genotypes of upland rice varieties were differentiated into several classes of Al tolerance, with frequency distribution of the classes that sometimes differed between the accessions of the same varieties. The effect of Al tolerance on root length was closely correlated with depression by Al in root dry weight and whole-plant P content. A source for adaptation to soil acidity for exploitation in the genetic improvement of aerobic and rainfed rice is clearly found among local upland rice varieties grown on acidic soils. However, the variation in tolerance to soil acidity within and among the seed lots of the same varieties maintained by individual farmers as well as among the varieties needs to be taken into consideration.

Fragrance, which plays an important role in determining the economic value of rice to growers and consumers, is known to be controlled by the Badh2 gene. This study evaluated the grain quality characteristics and allelic variation of the Badh2 gene in 22 fragrant rice landraces from Thailand. The rice seed samples from farmers’ storage facilities in northern, northeastern and southern Thailand, plus two advanced breeding lines and three check varieties, were evaluated for seed morphology and grain quality, and their Badh2 genes covering intron 4 to intron 8 were re-sequenced. Almost all of the landraces were classified as large grain types, with medium to high gelatinization temperatures. The variation in the Badh2 gene by haplotype analysis correlated with grain aroma by sensory evaluation. The badh2-E7 was found in haplotype 1 with a strong aroma in KH, NDLP, and PLD, as in KDML105 and the moderately aromatic BNM-CMU, BNM4, and SKH, along with PTT1. Three haplotypes had different positions of SNP on the Badh2 gene with varying results in the sensory test. The present results suggest that some rice varieties could be potentially introduced as genetic resources for fragrant rice breeding programs or could be developed to highly palatable cultivars with geographical indications to increase the income of highland farmers.