Morphological variation of iron toxicity tolerance in lowland rice (Oryza sativa L.) varieties

Rice (Oryza sativa L.) is a staple food crop in many countries in Africa. Africa consumes 11.6 million tons of rice per annum and out of 39 rice-producing countries, 21 import 50% to 99% of their rice requirements. The inability to reach the yield potential that would sustain Africa’s need for rice is due to many biotic and abiotic constraints that rice production faces. In lowland grown rice, one of the abiotic factors hindering rice production is iron toxicity. Excess uptake of ferrous (Fe2+) ions leads to a physiological stress, which results, into poor production. The current study aimed at selection of varieties tolerant to iron toxicity and assessment of the genetic diversity linked to this trait. In a hydroponic experiment conducted in a screen house at Africa Rice Centre in Dar es Salaam, 32 rice varieties were evaluated for tolerance to iron toxicity. The experiment was laid out in a split plot design with iron concentration as the main plot factor and variety as the sub plot factor. Two levels of iron concentration were used: 2 ppm and 300 ppm of Fe2+ as control and test concentrations, respectively. Traits observed to gauge tolerance were leaf bronzing (an indicator of iron toxicity), plant height, tillering, number of leaves, shoot weight (above ground), root length and root weight. The varieties ARICA8, and CK801 were found to be tolerant due to low bronzing indices, higher shoot weight, more number of leaves and lack of significant variation in morphology between the two Fe treatments except for the plant height. Correlation analysis depicted negative correlation between leaf bronzing and the other traits measured especially shoot biomass.

Nutrient variability of rice landraces (Oryza sativa L.) from Manipur, Northeast India and its nutrients supply potential in rice-based diets

Purpose Rice landraces are essential for supplying beneficial traits for developing improved rice varieties with better nutritional quality. Nevertheless, in a yield-driven environment, grain nutritional quality has been ignored especially that of rice landraces. Given this, the purpose of this study is to evaluate the content and nutritional variability of rice landraces from Manipur. Design/methodology/approach Thirty-three most popular rice landraces were collected as dry paddy samples from Manipur and transported to the National Institute of Nutrition, Hyderabad, by air. All the paddy samples were processed and analyzed for 35 nutrient parameters using standard methodologies. Findings The mean nutrient content of Nagaland brown rice was: protein 7.5 ± 0.8, fat 3.0 ± 0.3, TDF 5.5 ± 0.4 and ash 1.2 ± 0.2 g/100g. The range of water soluble-vitamin content in mg/100g, was 0.1–0.43 for Thiamine and for Niacin 2.1–3.5, while the content in µg/100g was 40–64 for Riboflavin, 0.5–3.9 for Pantothenic acid and 20–118 for Pyridoxine. A relatively large coefficient of variation was observed for iron (25%), manganese (28%), copper (32%), calcium (13%) and phosphorus (11%). Manipur rice landraces have significantly higher total dietary fiber and lower phytate contents than modern varieties. Milling led to steep losses of nutrients, and limiting to 5% milling substantially improves nutrient retention in milled rice. Research limitations/implications Future nutrition interventions should use rice with superior nutrient quality to improve nutrient intakes. Manipur rice landraces conserved over generations can broaden the genetic base of breeding stocks especially in the face of climate change. Originality/value The paper presents comprehensive nutritional data of 33 rice landraces from the state of Manipur, India. The results indicate large nutrient variability even within these 33 rice landraces with important traits such as high total dietary fiber and low phytate contents. The study highlights the importance of conserving the existing rich genetic material of Manipur rice landraces to develop varieties that combine higher yields with stress tolerance and superior grain nutritional value to improve the food and nutrient security.

Engineered hybrid insecticidal protein improves resistance to lepidopteran insects in rice (Oryza sativa L.) and maize (Zea mays L.)

Though cry gene transformed crops have successfully revolutionized modern agriculture, it is still necessary to discover new Cry proteins to overcome potential threatens from the development of resistant insect populations. We swapped domain-IIIs with various Cry proteins and engineered seven chimeric proteins, aiming to produce new engineered hybrid insecticidal proteins. Seven recombinant proteins were expressed in Escherichia coli. Three proteins exhibited high toxicity against Asian corn borer in dietary exposure assays. Three hybrid proteins were further transformed to rice (cv. Jijing88) to determine their insecticidal activity. Cry1Ab/Gc hybrid proteins, Cry1Ab being replaced by the domain-III of Cry1Gc, showed significantly more toxic against rice stem borer than others. Furthermore, Cry1Ab/Gc gene was transformed into maize (cv. HiII), then backcrossed into commercial maize inbred lines (cv. Ji853 and Y822), and formulated into Xiangyu 998 hybrid to evaluate their commercial value. Transgenic maize performed significant resistance improvement to the Asian corn borer without affecting the yield, and this new protein did not have adverse effects on the environment. Our result proved domain-swapped could be used as an efficient method for exploring new cry genes and engineered hybrid insecticidal protein. Cry1Ab/Gc provides a new tool for Lepidopteran insects resistant management in rice and maize.

IDENTIFICATION OF PLANT UTILIZATION IN THE LIFE CYCLE CEREMONY OF THE KAILI DA'A TRIBE IN UWEMANJE VILLAGE, KINOVARO DISTRICT, SIGI REGENCY

The purpose of this study was to obtain information about the types of plants used by the Kaili Da’a tribe in life cycle ceremonies that are still preserved for generations in Uwemanje village, Kinovaro district, Sigi district. The research population is all people who live in Uwemanje Village, Kinivaro District, which are spread over 4 hamlets. The research method uses survey research with the help of interview questionnaires. Interviews were conducted on key respondents and general respondents. Key respondents were selected by purposive sampling as much as 10% of the population, namely the people who were considered to be the most knowledgeable about the ins and outs of this ceremony, such as Sando, traditional leaders, village heads and village priests. Meanwhile, general respondents are people who are recommended by key respondents with a record that they are at least 30 years old and are married or have a family. The data and information in this study were processed descriptively. Types of plants/plants used in life cycle ceremonies consist of 21 species, namely: rice (Oryza sativa L.), coconut (Cocos nucifera L.), banana (Musa paradisiaca L.), cocor duck (Kalanchoe pinata L.), areca nut (Areca catechu L.), turmeric (Curcuma domestica L.), nail paci (Lawsonia enermis L.), bogenvil (Boganvillea glabra L.), pandanus (Pandanus amarylifolius L.), jatropha (Jatropha curcas), forest basil ( Ocimum sanctum L.), moringa (Moringa oleifera L.), shallot (Allium cepa L.), Bengal grass (Eleusine indica L.), hibiscus (Hibiscus tiliaceus L.), peacock flower (Caesalpinia pulcherima L.), betel (Piper betle L.), keluwih (Artocarpus camansi L.), jasmine (Jasminum sambac L.), palm sugar (Arenga pinnata), and red sugar cane (Saccharum officinarum L.). The percentage of utilization of plant parts that are most directly utilized is the leaves which amount to 14 with a percentage of 65.66%, flowers amount to 4 to 16.67%, fruit to reach 3 to 12.5%. The least used parts are rhizomes, seeds, tubers, roots and stems with a percentage of 5.17%.

Main Controlling Factors and Empirical Models for Total Mercury and Methylmercury Accumulation in Rice (Oryza Sativa L.)

It has been reported that rice consumption is the main mercury (Hg) exposure pathway for humans, and soil properties could significantly affect the methylation and accumulation process of Hg in soil-rice system. In this study, 19 paddy soil with various properties were spiked with exogenous Hg(II) at three concentration levels to conduct a pot experiment after a 60-days aging period. Stepwise multiple linear regression was applied to determine the controlling soil factors and develop prediction models for the methylmercury (MeHg) concentration in soil and total Hg (THg) and MeHg in brown rice. The results showed that THg in brown rice was positively correlated with THg in soil, while it had a negative correlation with soil pH and clay content. Soil organic matter (OM) promoted Hg methylation and inhibited the accumulation of MeHg in brown rice. Soil pH and clay content were negative factors when soil MeHg was used to predict MeHg in brown rice. THg and MeHg in brown rice could be well predicted by soil THg, pH and clay content. These results may provide a theoretical basis for safe production of rice in Hg contaminated paddy field.

Localization of QTL for cold tolerance at the germination stage of rice (Oryza sativa L.) using recombinant inbred lines

The cold tolerance of germinating direct-sown rice (Oryza sativa L.) has an increased rate of emergence, which ensures vigorous seedling growth. Research on QTL localization for cold tolerance at the germination stage can assist in molecular marker-assisted selection and enhance breeding efficiency. In this study, 94 populations of recombinant self-incompatible lines from Heigu and Ha 9366 were selected to investigate germination rates at low temperatures. It was found that two QTL loci (qLTG-3 and qLTG-12) were located at different germination times on chromosomes 3 and 12, respectively. The two QTLs at three different germination times, located using QTL, accounted for 21.3–25.9% of the phenotypic variation. Moreover, a reciprocal effect was detected between the two QTLs. The double QTLs increased the germination rate by 22–27% in this population. Additionally, qLTG-12 improved cold tolerance at the seedling stage. The results of this study might provide the materials and molecular markers for future molecular marker-assisted breeding for cold tolerance at the germination stage.

Characterization of Multiple Grain Rice (Oryza sativa L.) Biramsundari from Bangladesh

Biramsundari is a rice germplasm from Bangladesh showing one to four grain in a single seed. Comparative study of morphological traits revealed that BS is a taller rice variety compared to modern rice varieties with longer and wider flag leaves, longer panicle length and higher thousand seed weight (TSW) than transplanted aman rice variety BRRI dhan 49. Flower morphological analysis unveil that multiple grains of Biramsundari are originating from multiple number of carpels in each floret. About 40.1% flower contains three carpels. Fluorescent microscopic study also confirms the zygotic origin of multiple grain formation in Biramsundari. Molecular characterisation of Biramsundari was performed by using TeaCpSSR27 and TeaCpSSR28 chloroplast microsatellite markers. The results of this investigation reveal that atpF and rsp14-psaB intergenic spacer regions of Biramsundari have variation compared to sequences of with O. sativa ssp. indica, O. sativa ssp. japonica and O. rufipogon. Plant Tissue Cult. & Biotech. 31(2): 115-122, 2021 (December)