Ratoon Tillers Research Articles

Effects of Different Water Managements on Grain Yield and Grain Quality in Ratoon Rice Cultivation

Background: Ratoon rice production is one of the rice cultivation technologies with the potential to reduce labor and increase yield rate under a shorter cultivation time. However, few studies have focused on the effects of different water management on grain yield and quality. Objective: The aim of this study was to explore the effects of different water management on grain yield and quality in ratoon rice. Methods: Three water management treatments were followed- Control with the water level 5 cm aboveground, underground water treatment (UWT) with the water level 12 cm below the soil surface, and deep water treatment (DWT) with the water level 20 cm aboveground. The grain yield, yield components, amylose and protein content, and grain characteristics for grain quality were measured. Results: During the ratoon season, UWT had the highest grain yield of the three treatments. DWT had the highest ratoon tiller number but had a lower grain yield due to the increase in the number of ratoon tillers. The 1000-grain weight decreased markedly for DWT. With respect to grain quality, ratoon rice has a higher amylose content and a lower protein content than the main crop rice. UWT had the lowest protein content in the ratoon period and a higher grain yield. Conclusion: Yield performance in UWT is considered optimal for ratoon rice cultivation. However, grain quality under different water management did not show remarkable results. Therefore, the practice of fertilization during cultivation is recommended to improve grain quality.

Evaluation of cropping method for perennial ratoon rice: Adaptation of SALIBU to triple-cropping in Vietnam

Background: Generally, the yield of ratoon rice is at most 50% of the main crop. However, a cropping method “SALIBU” achieved more yield than the main crop and enables the perennial cropping. Although the SALIBU method is implementing 10 additional management practices to conventional method in Indonesia, the effect of each management practice is unclear. Methodology: We evaluated the effect size using an L 16 orthogonal array design pot experiment in triple-cropping rice in Vietnam. The robustness was checked by duplicating the experiment under standard and poor conditions. Results and Discussion: Positive large effects were shown in the poor conditions only. Cutting twice most affected the number of ratoon tillers. Importantly, the effect was positive under poor conditions but negative under standard conditions. Late irrigation had a robust negative effect. No treatment is effective in the triple-cropping of standard conditions. The SALIBU includes practices with unstable, negative, or minimal effects. The unstable effects show the interaction with the condition. The practices that have negative effects should exclude. Using practice on small effect size should depend on a cost-benefit analysis. Conclusions: No additional practice is effective for changing the triple-cropping to perennial ratoon cropping except harvesting near the ground. However, further work will be conducted to clarify the interaction between cutting twice and the cultivation condition.

Ratooning as a management strategy for lodged or drought-damaged rice crops.

Rice (Oryza sativa L.) plants have the ability to develop ratoon tillers if the terminal growing point is lost, such as when the panicle has been aborted, matured, or harvested. We examined postharvest and midseason ratooning as management strategies for damaged rice crops, both in irrigated and rainfed conditions. Genotypic variation was observed in terms of postharvest ratoon tillering, midseason ratoon crop growth after lodging, and midseason ratoon crop growth after drought stress. The genotypic variation in postharvest ratoon tillering was related to stem carbohydrate levels at the time of main crop harvest and was affected by soil moisture levels at the time of main crop harvest. Drought‐tolerant varieties did not consistently show improved ratoon crop growth. After lodging, cutting stems at a height of 30 cm produced the highest numbers of ratoon tillers, and the contribution of the ratoon crop to the total harvestable grain yield was highest when the ratoon crop was initiated at earlier growth stages. The highest ratoon grain yields recovered from lodged crops ranged up to 3.58 t ha−1. Total grain yield after drought was improved by trimming the leaves and panicles only in certain conditions and did not appear to be correlated with stem carbohydrate levels. These results suggest that management strategies may be recommended to farmers that exploit the ratooning ability of rice for improved recovery after midseason crop damage.

Evaluation of cropping method for perennial ratoon rice: Adaptation of SALIBU to triple-cropping in Vietnam

Background: Generally, the yield of ratoon rice is at most 50% of the main crop. However, a cropping method “SALIBU” achieved more yield than the main crop and enables the perennial cropping. Although the SALIBU method is implementing 10 additional management practices to conventional method in Indonesia, the effect of each management practice is unclear. Methodology: We evaluated the effect size using an L 16 orthogonal array design pot experiment in triple-cropping rice in Vietnam. The robustness was checked by duplicating the experiment under standard and poor conditions. Results: Positive large effects were shown in the poor conditions only. Cutting twice most affected the number of ratoon tillers. Importantly, the effect was positive under poor conditions but negative under standard conditions. Late irrigation had a robust negative effect. Discussion: No treatment is effective in the triple-cropping of standard conditions. The SALIBU includes practices with unstable, negative, or minimal effects. The unstable effects show the interaction with the condition. The practices that have negative effects should exclude. Using practice on small effect size should depend on a cost-benefit analysis. Conclusions: No additional practice is effective for changing the triple-cropping to perennial ratoon cropping except harvesting near the ground. However, further work will be conducted to clarify the interaction between cutting twice and the cultivation condition.

Evaluation of cropping method for perennial ratoon rice: Adaptation of SALIBU to triple-cropping in Vietnam

Background: Generally, the yield of ratoon rice is at most 50% of the main crop. However, a cropping method “SALIBU” achieved more yield than the main crop and enables the perennial cropping. Although the SALIBU method is implementing 10 additional management practices to conventional method in Indonesia, the effect of each management practice is unclear. Methodology: We evaluated the effect size using an L 16 orthogonal array design pot experiment in triple-cropping rice in Vietnam. The robustness was checked by duplicating the experiment under standard and poor conditions. Results and Discussion: Positive large effects were shown in the poor conditions only. Cutting twice most affected the number of ratoon tillers. Importantly, the effect was positive under poor conditions but negative under standard conditions. Late irrigation had a robust negative effect. No treatment is effective in the triple-cropping of standard conditions. The SALIBU includes practices with unstable, negative, or minimal effects. The unstable effects show the interaction with the condition. The practices that have negative effects should exclude. Using practice on small effect size should depend on a cost-benefit analysis. Conclusions: No additional practice is effective for changing the triple-cropping to perennial ratoon cropping except harvesting near the ground. However, further work will be conducted to clarify the interaction between cutting twice and the cultivation condition.

Evaluation of cropping method for perennial ratoon rice (SALIBU).

Background: Generally, the yieldof ratoon rice is at most 50% of the main crop. However, a cropping method "SALIBU" achieved more yield than the main crop and could be used for the cultivation of perennial cropping. Although the SALIBU method is implementing 10 additional management practices to conventional method, the effect of each management practice is unclear. Therefore, we aimed to evaluate the effect size and the robustness of each management practice. Methodology: We evaluated the effect size using an L 16orthogonal array design pot experiment. For the robustness, we duplicated the experiment under both standard and checked whether the practice shows the same effect size. The bad conditions were low plant density, no fertilization, continuous flooding water management, and late harvesting. Results: The ratoon rice yield was proportional to the number of ratoon tillers used as in conventionally produced ratoon rice. Late cutting was most affected to the number of ratoon tillers. Importantly, this effect was reversed; the effect was positive under bad conditions, but was negative under standard conditions. Furthermore, late irrigation, a recommended management practice, had a robust negative effect on ratoon tillers and yield under both the conditions. Positive large effects were shown in the bad condition only. Discussion: Our results show that the SALIBU cropping method includes practices with unstable, negative, or minimal effects.The practices have unstable effects should be clarifying the interaction with the condition. The practices that have negative effects should exclude. Using practice on small effect size should depend on a cost-benefit analysis. Conclusions: SALIBU will be acceptable to the Mekong Delta triple cropping rice cultivation without the additional practice of original SALIBU cropping method. However, further work is needed to clarify the interaction between late cutting and the cultivation condition, and on the negative effect of late irrigation.

Nutrient application improves stubble bud sprouting under low temperature conditions in sugarcane

A study was undertaken to enhance the stubble bud sprouting under low temperature conditions by application of calcium (as CaCl2), potassium (as KCl) and manganese (as MnCl2) each at the rate of 0.5% solution. Stubble bud sprouting under controlled condition was about 64.3%, 73%, 68.7% due to calcium, potassium and manganese treatment respectively as compared to untreated check (46.0%). The number of ratoon tillers per stubble, as recorded after 60 days of ratoon initiation, was 157%, 57%, 85.7% more in the calcium, potassium and manganese treatment respectively. Weight of buds, tillers and roots was found maximum with manganese treatment followed by calcium and potassium treatment. Results suggested an improvement in stubble bud sprouting and subsequent regrowth of stubble in winter-initiated ratoon by nutrient application, which may help in enhancing ratoon productivity.

Systems biology or the biology of systems: routes to reducing hunger

Systems biology or the biology of systems: routes to reducing hunger

Ethephon : A versatile growth regulator for sugar cane industry

In many sugarcane growing areas of the world, sugar productivityper se is low due to physio-biochemical constraints and adverse climatic conditions during growth and ripening. The cane growth and sucrose accumulation are severely impeded due to many factors such as poor sprouting and low tillering, climatic impediments during cane maturation, poor sprouting of winter initiated ratoon, sub-optimal quality of stand-over crop and undesired flowering in commercial sugarcane plantation. Plant growth regulators have been found to mitigate the adverse affects of these constraints to some extent. Studies carried out at many places show that application of plant growth regulating chemical such as ethephon (ethrel or 2-chloroethyl phosphonic acid) leads to enhancement in seed cane sprouting under normal and late-planted conditions. The tiller number, millable canes, and biomass productivity per unit area increases following ethephon treatment. It’s efficacy has been demonstrated in improving sprouting of winter initiated ratoon of early maturing varieties, with consequent increase in ratoon tillers at a later stage. Ethephon also hastens the cane maturation process which favours early milling and suppresses flowering as well as sustains quality during late-milling. Ethephon application on sugarcane could be an important agrotechnology from cane grower’s and miller’s point of view due to its multiple benefits. It is an eco-friendly chemical and has tremendous potential to augment cane yield and sugar productivity.

Screening Oryza Species Plants for Rice Sheath Blight Resistance.

Rice wild relatives, Oryza species, are one possible source of sheath blight (Rhizoctonia solani) resistance genes. However, Oryza spp. cannot be screened in the field as is done for cultivated rice (O. sativa) because the plant canopy does not favor disease development and many plants drop mature seed. Thus, a growth chamber-greenhouse method of screening Oryza spp. and their early generation progeny is needed. Primary-secondary and ratoon tillers of rice cultivars-germplasm which ranged from moderately resistant to very susceptible were evaluated first for sheath blight susceptibility. Plants were inoculated by placing R. solani-colonized toothpicks at the leaf collar, then incubating plants in a growth chamber. After 7 days, plants were visually rated for sheath blight severity, and the lesion length of each leaf was measured. Ranking of cultivar-germplasm susceptibility by visual rating of primary-secondary tillers corresponded to the ranking from field ratings. Visual ratings correlated best with combined lesion length of the second and third leaves. For ratoon tillers, visual ratings correlated best with second-leaf lesion length. Next, this method was used with ratoon tillers to evaluate sheath blight susceptibility of 21 Oryza spp. accessions and F1 progeny from crosses between 17 accessions and cultivated rice. This method proved useful on a limited scale for screening germplasm that could not be evaluated under field conditions.

Studies on Lateral Buds Growth into Ratoon Tillers in Early-season Culture of Rice Plants.

The yielding ability and the effect of fertilization on yield were investigated in ratoon crop rice in early-season cultures. The total leaf number of each tiller in the ratoon crop was compared with Katayama's theoretical total number of leaves. The ratoon crop produced about 30% of the grain yield of the parent crop. Fertilization of the ratoon crop increased the panicle number per hill, resulting in an increased yield. Ratoon tillers were separated from the main stem to determine their tillering position on the stem, and to find the effect of fertilization on regrowth of tillers. Yield increase by fertilization was mainly due to the increase in the number of ripened secondary tillers. Tillers had 2∼3 more leaves than the total leaves expected from the theory of synchronous growth of leaves and tillers. The investigation of growth of lateral buds at each growth stage of the parent crop showed that the relation between growth of the main stem and lateral bud growth of ratoon tillers was not synchronized, resulting in the increase of total leaf number over the theoretical one.

Influence of Variety, Irrigation, and N Level on Production of Effective Ratoon Tillers

Influence of Variety, Irrigation, and N Level on Production of Effective Ratoon Tillers

Phenology, early growth, and yield of planted and ratoon grain sorghum

Knowledge is limited on growth and development of ratoon grain sorghum [Sorghum bicolor (L.) Moench] in the field. In efforts to build simulation models of ratoon grain sorghum, modellers have assumed that the planted and ratoon crops grow similarily. This study was undertaken to document the growth of ratoon grain sorghum and test the hypothesis that growth and development of the ratoon crop is similar to the planted crop. Experiments were conducted from 1985 through 1987 under irrigated field conditions using nine hybrids of medium/medium-late maturity on a Houston Black clay: fine, montmorillonitic, thermic Udic Pellustert.In two of the three years, grain-yield of the planted crop exceeded the ratoon while grain-yield was equal in the other year studied. Rapid development of tillers produced much higher leaf-area indexes (L) and vegetative biomass early in the plant's ontogeny for the ratoon compared to the planted crop. Depending on hybrid and year, each primary shoot (PS) of the planted crop produced from 4 to 7 tillers within 20 days of harvest of the planted crop. At harvest, however, only 2–3 tillers/PS remained and only 1.7 tillers/PS (on average) produced grain.The planted crop allocated a higher proportion of its total above-ground biomass to grain than did the ratoon crop. Differences in the degree of tillering and partitioning of biomass to grain were found among hybrids. Yet, a significant hybrid×year interaction suggests that partitioning was dependent on the environment. Phenology of planted and ratoon crops were similar. Grain-forming tillers produced the same number of leaves as the primary shoot of the planted crop, and differences in time to anthesis between the planted and ratoon crops averaged approximately 100 of the 1000 heat units (7°C base temperature). Based on our observations, the assumption that growth of planted and ratoon grain sorghum are similar appears to be in error. However, the phenology of grain-forming ratoon tillers appeared to mimic the phenology of the planted crop's primary shoot.

Application of ratoon traits obtained by higher cutting for estimation of percentage of ripened grains in rice plants.

The effect of the cutting height on the relationship between ratoon traits and the percentage of ripened grains of the uncut plant was investigated using 30 rice cultivars grown in a randomized block design with 2 replications. Variations from year to year of ratoon traits were also investigated. The plant was cut on the 10th day after heading at four different heights, i. e., at ground levcl, and at 5, 10 and 20cm above the ground. The percentage of missing hills increased as the cutting height decreased. The percentage of ratoon tillers and the ratoon height increased with the increase of the cutting height. The relationship between ratoon traits and the percentage of ripened grains of the uncut plant varied with the cutting height. Increased. cutting heights gave significantly higher values for the correlation coefficients between the percentage of ratoon tillers and the percentage of ripened grains. However, the ratoon height was not significantiy correlated with the percentage of ripened grains regardless of the cutting height. The year-to-year correlation of ratoon traits was significant and positive, although growth was different. The correlation coefficient was largel for the percentge of ratoon tillers than for the ratoon height. This suggests that the percentage of ratoon tiliers obtained by cutting at 10 or 20cm above the ground may reflect the percentage of ripened grains of the uncut plant.

Application of ratoon to a test of agronomic characters in rice breeding II. The relationship between ratoon ability and lodging resistance.

The relationship between ratoon ability and lodging resistance was investigated with 21 paddy cultivars grown in a randomized block design with 2 replications. Plant characters concerned with lodging such as internode weight, stem base weight, breaking strength of culm and lodging index were noted at 5 successive 10 days intervals starting on the day of heading. Internode weight, stem base weight and breaking strength increased during the first 10-days period following heading then declined during the next 10- or 20-days period, but reached again the levels at heading or beyond on 40 days following heading. Lodging index increased during the 30-days period following heading, and then declined down. The rice plant was also cut at 5cm above the ground at 5 different growth stages, i.e the day of heading, and 10, 20, 30 and 40 days after heading. Some characters of the ratoon crops were surveyed at the ripening stage. Percentage of ratoon tillers showed the same change as internode weight, stem base weight and breaking strength. Changes of the percentage of ratoon tillers and the ratoon height showed a similar tendency in cuttings during the period from 10 days after heading to 40 days. Traits of the ratoon did not show any clear relationship to breaking strength. However, there were significant and negative correlations between traits of the ratoon and lodging index in cuttings on 20, 30 and 40 days following heading. It was suggested from these correlations that ratoon ability might be used as a test indicator of lodging resistance. The contribution rate of leaf sheath to breaking strength ranged approximately from 15% to 40% in the later period of ripening, and it was depended on cultivars and growth stages.

Application of Ratoon to a Test of Agronomic Characters in Rice Breeding. I. Variation in Ratoon Ability and Its Relation to Agronomic Characters of Mother Plant

30 cultivars of paddy were growh in a randomized block design with 4 replications. The rice plants were cut at 5cm above the ground at 4 different growth stages, i, e. 10, 20, 30 and 40 days after headingf. Ratoon weight, ratoon height and percentage of ratoon tillers to that of mother plant, were recorded 40 days after cutting. With respect to the 3 ratoon characteristics a significant decrease was observed to occur when the cutting time was delayed from 10 to 20 days after heading. The increase in the subsequent cutting was less marked. Analysis of variance suggests that ratoon weight, ratoon height and percentage of ratton tillers are heritable. In cuttings made 10 and 20 days after heading, there was a positive and highly significant phenotypic correlation between percentage of ripened grains of mother plant and these ratoon traits. Heritabilities in the broad sense for the ratoon traits became higher in the order, ratoon weight, ratoon height, percen-tage of ratoon tillers. Moreover, the heritability of percentage of ratoon tillers was nearly equal to that of culm length and panicle length. These facts show that ripening ability of rice plant may be tested by observing the ratoon, especially percentage of ratoon tillers.

Rust-Resistant Wheats for India

ALL the three rusts of wheat occur in India. It has been shown that in the plains of India the severe summer heat kills the rust spores and that the wheat crop is infected anew each season by spores blown down from the hills, where wheat is cultivated up to an altitude of about 9,000 ft. above sea-level. The barberry, though common in the hills, seems to play little part in the annual recurrence of black rust1, and it is the self-sown wheat plants and ratoon tillers from harvested plants in the hilly areas which constitute the most obvious means of carry-over of rusts from year to year.