Yosep S. Mau
Department of Agrotechnology, Faculty of Agriculture, Universitas Nusa Cendana. Jl. Adisucipto, Penfui, Kupang 85001, East Nusa Tenggara, Indonesia

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Brown spot disease severity, yield and yield loss relationships in pigmented upland rice cultivars from East Nusa Tenggara, Indonesia Yosep S. Mau; Antonius Ndiwa; Shirly Oematan
Biodiversitas Journal of Biological Diversity Vol. 21 No. 4 (2020)
Publisher : Society for Indonesian Biodiversity

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/biodiv/d210443

Abstract

Abstract. Mau YS, Ndiwa ASS, Oematan SS. 2020. Brown spot disease severity, yield and yield loss relationships in pigmented upland rice cultivars from East Nusa Tenggara, Indonesia. Biodiversitas 21: 1625-1634. Brown spot is one of the most devastating diseases of rice, which could lead to total yield loss. The disease has a worldwide distribution, more specifically in areas where water supply is scarce, most specifically in the dry upland areas. Almost all stages of rice are affected by the disease, where leaves and grains are mostly affected. Considerable differences exist in susceptibility to brown spot among rice varieties, which may cause a large variation in yield loss caused by the disease. Therefore, the resistance level of rice varieties and their yield reduction has to be regularly evaluated and updated. There are only a few reports on the relationship between brown spot severity with yield and yield loss of upland rice, and is even lacking in pigmented upland rice. The objectives of the present study were to assess the brown spot severity and resistance level in pigmented upland rice cultivars from East Nusa Tenggara Province, Indonesia, and to elucidate their relationships with yield and yield reduction. Twenty four pigmented upland rice genotypes were evaluated in the field during May to October 2019, and their disease responses and yields were recorded. Disease severity was observed weekly and used to calculate Area Under the Disease Progress Curve (AUDPC) for comparison among the genotypes. The relationships between disease severity and AUDPC with yield and yield loss were also examined. The results showed significant variation in brown spot severity and AUDPC, ranging from, respectively, 11.11% to 40.70% and 398.42%-days to 1081.30%-days. Yields and yield losses of test genotypes also varied substantially. Yields under diseased-free and diseased plots ranged from, respectively, 2.34 t ha-1 to 6.13 t ha-1 and 1.68 t ha-1 to 3.74 t ha-1 while yield loss was between 10.46% and 56.15%. Six genotypes were moderately resistant, four genotypes were moderately susceptible and 14 genotypes were susceptible to brown spot. Neither disease severity nor AUDPC had a linear relationship with yield but both exhibited positive and linear relationships with yield loss.
Variations of grain physical properties, amylose and anthocyanin of upland red rice cultivars from East Nusa Tenggara, Indonesia Jenny E.R. Markus; Antonius S.S. Ndiwa; Shirly S. Oematan; Yosep S. Mau
Biodiversitas Journal of Biological Diversity Vol. 22 No. 3 (2021)
Publisher : Society for Indonesian Biodiversity

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/biodiv/d220335

Abstract

Abstract. Markus JER, Ndiwa ASS, Oematan SS, Mau YS. 2021. Variations of grain physical properties, amylose and anthocyanin of upland red rice cultivars from East Nusa Tenggara, Indonesia. Biodiversitas 22: 1345-1354.  Red rice is becoming more popular nowadays due to the increasing awareness of rice consumers on its health benefits. The demands for red rice are increasing but the supply is limited, thus, local red rice cultivars can be used to fill this gap. Optimal use of local rice germplasm requires a comprehensive evaluation of their traits, and the genotypes having the most desirable traits can be selected for direct use. Several upland red rice cultivars from East Nusa Tenggara Province have been evaluated for various traits while their grain properties are still unrevealed. Information on grain properties is important, both for consumer preference and rice breeders. This study aimed to elucidate the grain physical properties, amylose, and anthocyanin of upland red rice germplasm from ENT Province, and to identify genotypes with the most desirable characters for further employment. Eighteen rice genotypes were used in this study. They were cultivated in the field, and the harvested grains were analyzed in the laboratory. Both ANOVA and descriptive statistics were used for data analysis. Substantial variations were observed on all variables, except the chalky grain percentage. The kernel length of tested genotypes was classified as long, medium, and short while the kernel shapes were slender, medium, and bold. Most tested genotypes had high head rice percentage and low to medium percentages of large and small broken kernels. Chalky grain was almost absent. Amylose content ranged from 1.0% to 28% while anthocyanin was about 1.0 - 20 mg/100 g. The evaluated genotypes were clustered into three main groups. Percentages of large and small broken kernels, and amylose content were mostly responsible for the observed variations among the rice genotypes. The red rice genotypes were diverse in the studied characters, thus, those with desirable grain characters are useful for further development and utilization.