Kenji Irie

• Tokyo University of Agriculture

Drought limits water availability and negatively impacts rice growth. One of the strategies to overcome drought stress is the genetic improvement of root traits by marker-assisted selection (MAS). Using the MAS strategy, pyramiding quantitative trait loci (QTLs) efficiently stacks multiple QTLs. To elucidate the effects of pyramiding root QTLs on s...

Objective The aim of the study was to investigate the quantitative association between the dietary intakes of children and their caregivers. Method In this cross‐sectional study, a non‐consecutive 2‐day 24‐h dietary recall was conducted in two seasons. Participants comprised 142 pairs of 12–59‐month‐old children and their female caregivers from ru...

Background An initiative aimed at improving nutrition intervention programs by providing food consumption data for better decision-making and promoting local foods has led to the development of an application-based food assessment tool called the Agrobiodiversity and Diet Diagnosis for Interventions Toolkit (ADD-IT). A new food frequency questionna...

The present study aimed to clarify the differences in nutritional intake in relation to the consumption of local food products and dietary patterns between two rural Kenyan regions, Kitui and Vihiga, where different ethnic groups live in different agro-ecological zones. A participant observation study with weighted dietary records was conducted in...

In this field survey of seed system dynamics in Myanmar, the authors note that the country’s dominant system of traditional agriculture faces pressure from the introduction of ‘improved’ varieties and shifts in policy. However, farmers—from small and subsistence growers to large-scale rice producers—continue to raise indigenous species. One is chin...

This study aimed to investigate whether the Kenyan Food Pyramid (FP) can evaluate excess or insufficient nutrient intake. Participants were farmers (56 men and 64 women, aged 18–60 years) in Wangige Village, Kiambu County—a peri-urban area of Kenya. Cross-sectional data were collected for demographic characteristics, physical measurements, and 2-da...

A deep-rooting upland rice variety (Kinandang Patong) was evaluated for its growth response to bio-fertilization at early stages. Five non-native plant growth-promoting bacteria previously isolated from yams (Dioscorea spp.) were inoculated to upland rice under growth chamber and greenhouse conditions. Effects of the inoculation varied depending on...

Understanding germplasm diversity is valuable in improving underutilized water yam (Dioscorea alata L.) diversity. In this study, we investigated intra-specific genetic diversity based on morphological traits, SSR polymorphisms and ploidy levels in water yam accessions collected from Myanmar, Papua New Guinea (PNG) and Japan. The results of agro-mo...

The volume that the root system can occupy is associated with the efficiency of water and nutrient uptake from soil. Genetic improvement of root length, which is a limiting factor for root distribution, is necessary for increasing crop production. In this report, we describe identification of two QTLs for maximal root length, QUICK ROOTING 1 (QRO1)...

Water yam (Dioscorea alata L.) are adaptable to cultivation under different soil conditions. This study aimed to reveal the effects on the growth of water yam under natural alkaline soil conditions (called Shimajiri Mahaji locally) at the Miyako Islands, Okinawa Prefecture in 2011 and under three fertilizer levels and varied pH in the greenhouse at...

Genus Vigna comprise several domesticated species including cowpea and mungbean, and diverse wild species. We found an introgressive hybrid population derived from two wild species, Vigna umbellata and Vigna exilis, in Ratchaburi district, Thailand. The hybrid was morphologically similar to V. umbellata but habituated in a limestone rock mountain,...

Somaclonal variations in pigmentation occurred repeatedly during the clone propagation of the landrace ‘Okinawa A’ of water yam, Dioscorea alata L. An initial variation appeared when clone propagation of ‘Okinawa A’ started in 2000. Reverting variants, closely resembling the original type appeared several times during the cloning of the initial var...

Rice landraces in Myanmar show a wide range of variation in amylose content from 0 to 40%. A great diversity was observed in amylose content of rice landraces especially from such mountainous states as Chin, Kachin and Shan. The frequent appearance of very low (less than 4%) amylose landraces indicates some cultural influence of the waxy rice zone...

Water yam produces a single or a few tubers per plant and the rate of clonal propagation by tuber cutting is extremely low. Therefore, it is important to develop a more efficient method of clonal propagation by the use of vine cuttings. It is generally recognized that in the vine cuttings of water yam, axillary buds pre-differentiated on leaf axils...

Genetic diversity of Myanmar cultivated rice accessions was evaluated by DNA markers. The materials included 110 accessions from six different regions of Myanmar and 17 accessions from other countries.Twelve RFLP markers, 6 STS markers and 28 CAPS markers were used. An UPGMA dendrogram was constructed to infer the phylogenetic relationships of the...

Usually, cultivation of yam (Dioscorea alataL.) is practiced using seed tuber fragments obtained by cutting large tubers. We investigated the effect of the seed tuber size on the growth and development of yam, using two varieties; Lisiteye introduced from Papua New Guinea and a local variety from Africa. Tubers of the two varieties were cut into fr...

Four upland rice varieties namely Norin 26 (Japonica type), Yar 2 (Indica type) and NERICA 1 and NERICA 4 were grown in nutrient solutions separately deficient of one of the following elements: N, P, K, Ca and Mg, to examine deficiency symptoms as well as the effects on growth and grain yield. All varieties showed similar response to any of the def...

This study aimed to investigate the varietal difference in lodging recovery of rice seedling (negative gravitropism), which might be related to the suitability for seedling establishment in direct-seeding cultivation. Characteristics of general features of rice varieties which were collected from different countries were studied, focusing on the co...