A CRITICAL ASSESSMENT OF THE IMPORTANCE OF SEEDLING AGE IN THE SYSTEM OF RICE INTENSIFICATION (SRI) IN EASTERN INDIA

A survey of the system of rice intensification (SRI)-related literature indicates that different authors have drawn conflicting inferences about rice yield performances under the SRI, chiefly because the SRI methodology has been variously advocated, interpreted and implemented in the field using different rice varieties, seedling ages at transplantation, cultivation seasons and nutrient management regimes. In particular, the SRI method of single-seedling transplantation (SST) has potential economic advantage due to reduced seed costs, but it is not clear whether SST is an effective management strategy across a range of seedling ages, and whether there is any specific seedling age that is optimal for yield improvement of a given rice variety. This is an important consideration in rain-fed ecosystems where variable rainfall patterns and lack of controlled irrigation make it difficult to reliably transplant at a specific seedling age as recommended for the SRI. We conducted a five year-long experiment on a rain-fed organic farm using a short-duration upland and a medium-duration lowland landrace, following the SRI methodology. Rice seedlings of different ages (6, 10, 14, 18 and 28 days after establishment) were transplanted at 25 cm × 25 cm spacing in three replicated plots. The performance for each landrace was examined with respect to productive tillers, panicle density, total grain counts per hill and grain yield per unit area. Performances of seedlings of different ages were compared with that of control plots that employed all SRI practices with the exception that 28-day-old seedlings were transplanted with three seedlings per hill. The results indicate that (1) the SRI can improve mean panicle density if seedling age ≤ 18 days, but that responses differ between varieties; (2) the number of productive tillers per hill is significantly less in SST than that of multiple seedling transplants (MST) of 28-day-old seedlings of both upland and lowland varieties; (3) the total grain numbers per hill of the lowland variety is significantly greater for 14-day-old SST than 28-day-old MST; (4) the grain yield per unit area from young SRI transplants is significantly greater than that from 28-day-old MST for the lowland variety, although the magnitude of the improvement was small; (5) for the upland variety, grain yields declined with the oldest seedlings, but planting multiple seedlings per hill made the yield of the oldest transplants on par with that of younger seedlings planted singly. Our findings suggest that transplanting younger seedlings under the SRI management may not necessarily enhance grain yield

A critical assessment of the importance of seedling age in the system of rice intensification (sri) in Eastern India

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.A survey of the system of rice intensification (SRI)-related literature indicates that different authors have drawn conflicting inferences about rice yield performances under the SRI, chiefly because the SRI methodology has been variously advocated, interpreted and implemented in the field using different rice varieties, seedling ages at transplantation, cultivation seasons and nutrient management regimes. In particular, the SRI method of single-seedling transplantation (SST) has potential economic advantage due to reduced seed costs, but it is not clear whether SST is an effective management strategy across a range of seedling ages, and whether there is any specific seedling age that is optimal for yield improvement of a given rice variety. This is an important consideration in rain-fed ecosystems where variable rainfall patterns and lack of controlled irrigation make it difficult to reliably transplant at a specific seedling age as recommended for the SRI. We conducted a five year-long experiment on a rain-fed organic farm using a short-duration upland and a medium-duration lowland landrace, following the SRI methodology. Rice seedlings of different ages (6, 10, 14, 18 and 28 days after establishment) were transplanted at 25 cm × 25 cm spacing in three replicated plots. The performance for each landrace was examined with respect to productive tillers, panicle density, total grain counts per hill and grain yield per unit area. Performances of seedlings of different ages were compared with that of control plots that employed all SRI practices with the exception that 28-day-old seedlings were transplanted with three seedlings per hill. The results indicate that (1) the SRI can improve mean panicle density if seedling age ≤ 18 days, but that responses differ between varieties; (2) the number of productive tillers per hill is significantly less in SST than that of multiple seedling transplants (MST) of 28-day-old seedlings of both upland and lowland varieties; (3) the total grain numbers per hill of the lowland variety is significantly greater for 14-day-old SST than 28-day-old MST; (4) the grain yield per unit area from young SRI transplants is significantly greater than that from 28-day-old MST for the lowland variety, although the magnitude of the improvement was small; (5) for the upland variety, grain yields declined with the oldest seedlings, but planting multiple seedlings per hill made the yield of the oldest transplants on par with that of younger seedlings planted singly. Our findings suggest that transplanting younger seedlings under the SRI management may not necessarily enhance grain yields

Colour based nutraceutical potential of some traditional rice (Oryza sativa L. ssp. indica) varieties of India

153-157Consumption of unpolished grain, rather than polished grain has become a modern trend and consumers are mainly putting their thoughts and effort to consume products with more antioxidant capacity. Rice is the main staple food and apart from being considered as the main source of energy, it contains many nutraceutical properties because of its enriched secondary metabolites. This study is an effort to bring back the indigenous traditional rice landraces that almost disappeared from the farm fields after the advent of the Green Revolution in India. This article focuses on colour-based nutritional properties of six coloured and four non-coloured indigenous rice varieties based on antioxidant potential, total phenol and flavonoid content along with secondary metabolites profiling by high performance liquid chromatography. The biochemical uniqueness of these varieties has been explored that opens the gate for the conservation of more indigenous rice varieties for food security, as a cheap source of nutritional food and to construct a better niche for public health in developing country like India

Colour based nutraceutical potential of some traditional rice (Oryza sativa L. ssp. indica) varieties of India

Consumption of unpolished grain, rather than polished grain has become a modern trend and consumers are mainly putting their thoughts and effort to consume products with more antioxidant capacity. Rice is the main staple food and apart from being considered as the main source of energy, it contains many nutraceutical properties because of its enriched secondary metabolites. This study is an effort to bring back the indigenous traditional rice landraces that almost disappeared from the farm fields after the advent of the Green Revolution in India. This article focuses on colour-based nutritional properties of six coloured and four non-coloured indigenous rice varieties based on antioxidant potential, total phenol and flavonoid content along with secondary metabolites profiling by high performance liquid chromatography. The biochemical uniqueness of these varieties has been explored that opens the gate for the conservation of more indigenous rice varieties for food security, as a cheap source of nutritional food and to construct a better niche for public health in developing country like India

A Farmer’s Approach to Detecting Photoperiod Sensitivity in Rice (Oryza sativa ssp. indica) Landraces

Most indigenous rice landraces are sensitive to photoperiod during short day seasons, and this sensitivity is more pronounced in indica than in japonica landraces. Attempts to identify photoperiod sensitive (PPS) cultivars based on the life history stages of the rice plant, and several models and indices based on phenology and day length have not been precise, and in some cases yield counterfactual inferences. Following the empirical method of traditional Asian rice farmers, the author has developed a robust index, based on the sowing and flowering dates of a large number of landraces grown in different seasons from 2020 to 2023, to contradistinguish PPS from photoperiod insensitive cultivars. Unlike other indices and models of photoperiod sensitivity, the index does not require the presumed duration of different life history stages of the rice plant but relies only on the flowering dates and the number of days till flowering of a rice cultivar sown on different dates to consistently identify photoperiod sensitive cultivars

The Erosion of Biodiversity and Culture: Bankura District of West Bengal as an Illustrative Locale

The decimation of biodiversity at the species, genetic, and ecosystem levels as a direct consequence of the industrial resource use mode is well documented in human ecology and conservation literature. Not only wild biota but also domesticated crop landraces have been pushed to extinction by industrial land-use systems. The process of biodiversity erosion impinges on, and is augmented by, the decimation of local cultural elements, such as food cultures, the vocabularies of local languages, house architecture, and an inchoate appreciation of the non-use value of biodiversity, i.e., beyond its instrumental value. This process of biocultural erosion is evident in the district of Bankura, West Bengal, India, and this article collates evidence from over two decades of my research on the biodiversity and cultural elements of the region. The replacement of a traditional eco-centric ethic with an industrial ethic, and its consequent impacts on biodiversity and local cultural traditions in this region, is illustrative of the global process of biodiversity loss

Phenotypic characters of rice landraces reveal independent lineages of short-grain aromatic indica rice

Rice landraces are lineages developed by farmers through artificial selection during the long-term domestication process. Despite huge potential for crop improvement, they are largely understudied in India. Here, we analyse a suite of phenotypic characters from large numbers of Indian landraces comprised of both aromatic and non-aromatic varieties. Our primary aim was to investigate the major determinants of diversity, the strength of segregation among aromatic and non-aromatic landraces as well as that within aromatic landraces. Using principal component analysis, we found that grain length, width and weight, panicle weight and leaf length have the most substantial contribution. Discriminant analysis can effectively distinguish the majority of aromatic from non-aromatic landraces. More interestingly, within aromatic landraces long-grain traditional Basmati and short-grain non-Basmati aromatics remain morphologically well differentiated. The present research emphasizes the general patterns of phenotypic diversity and finds out the most important characters. It also confirms the existence of very unique short-grain aromatic landraces, perhaps carrying signatures of independent origin of an additional aroma quantitative trait locus in the indica group, unlike introgression of specific alleles of the BADH2 gene from the japonica group as in Basmati. We presume that this parallel origin and evolution of aroma in short-grain indica landraces are linked to the long history of rice domestication that involved inheritance of several traits from Oryza nivara, in addition to O. rufipogon. We conclude with a note that the insights from the phenotypic analysis essentially comprise the first part, which will likely be validated with subsequent molecular analysis

Diversity of Flower Opening Time and Duration in Rice (Oryza sativa ssp. indica) Landraces of South and Southeast Asia in Different Cultivation Seasons

Different cultivars of rice (Oryza sativa) open at different times of the day, and the overlap of anthesis time in rice between the neighbouring cultivars is of crucial importance to the degree of cross pollination in rice. Nevertheless, none of the past experiments with cross pollination between different rice cultivars ever reported the respective flower opening time (FOT) and flower exposure duration (FED) of the parent cultivars, until recently. The authors present here the first record of FOT and FED of 1114 indica rice landraces of South and Southeast Asia, growing during summer and winter seasons in three consecutive years. The authors also present an analysis of the influences of the growing season on the anthesis behaviour, and present the first records of the FOT and FED variability on sunny and cloudy days of a large number of landraces. The data show that rice florets tend to open earlier in the morning (that is, take a shorter time to anthesis after sunrise) on sunny days than on cloudy days, and also significantly later during long day seasons (spring and summer) than during short day season (winter); and that FED is inversely related to both FOT and the length of duration from sunrise to first flower opening. The wide ranges of FOT (8:50 a.m. to 12:40 p.m.) and FED (15 to 194 minutes) also suggest the ample time window for receiving pollen from neighbouring cultivars with different FOT, enhancing the chances of cross pollination between hundreds of rice landraces with FOT and FED overlaps