Rice Culture Research Articles

Isolation of anticancer and anti-trypanosome secondary metabolites from the endophytic fungus Aspergillus flocculus via bioactivity guided isolation and MS based metabolomics

This study aims to identify bioactive anticancer and anti-trypanosome secondary metabolites from the fermentation culture of Aspergillus flocculus endophyte assisted by modern metabolomics technologies. The endophyte was isolated from the stem of the medicinal plant Markhamia platycalyx and identified using phylogenetics. Principle component analysis was employed to screen for the optimum growth endophyte culturing conditions and revealing that the 30-days rice culture (RC-30d) provided the highest levels of the bioactive agents. To pinpoint for active chemicals in endophyte crude extracts and successive fractions, a new application of molecular interaction network is implemented to correlate the chemical and biological profiles of the anti-trypanosome active fractions to highlight the metabolites mediating for bioactivity prior to purification trials. Multivariate data analysis (MVDA), with the aid of dereplication studies, efficiently annotated the putatively active anticancer molecules. The small-scale RC-30d fungal culture was purified using high-throughput chromatographic techniques to yield compound 1, a novel polyketide molecule though inactive. Whereas, active fractions revealed from the bioactivity guided fractionation of medium scale RC-30d culture were further purified to yield 7 metabolites, 5 of which namely cis-4-hydroxymellein, 5-hydroxymellein, diorcinol, botryoisocoumarin A and mellein, inhibited the growth of chronic myelogenous leukemia cell line K562 at 30 μM. 3-Hydroxymellein and diorcinol exhibited a respective inhibition of 56% and 97% to the sleeping sickness causing parasite Trypanosoma brucei brucei. More interestingly, the anti-trypanosomal activity of A. flocculus extract appeared to be mediated by the synergistic effect of the active steroidal compounds i.e. ergosterol peroxide, ergosterol and campesterol. The isolated structures were elucidated by using 1D, 2D NMR and HR-ESIMS.

Anther culture in rice: Progress and breeding perspective

Anther culture is an important biotechnological tool for the rapid recovery of fixed breeding lines in rice. The method is largely species- and genotype-specific. Indica rice is known to have a recalcitrant genetic background. Oryza glaberrima responds better to the anther culture than O. sativa while japonica sub-group is more responsive to microspore embryogenesis than Indica types. Media recipes and culture techniques have been standardized for callus induction and green plantlet regeneration using Indica and Japonica varieties as well as their inter se hybrids. Additive effects seem more important than dominant effects of the genes concerned for callus induction while preponderance of dominant effects is reported for regeneration response. Sexual hybridization of rice sub-groups (Japonica x Indica) followed by the selection of favourable QTL for green plant regeneration may be adopted to improve plant regeneration from anther-derived callus in Indica rice. However, genetic transformation technology using individual genes related to different aspects of anther culture could be a more direct approach. This paper reviews the progress and breeding perspective of anther culture in rice for genetic improvement of agronomic- and stress-related traits using double haploid breeding.

Antagonism between fungicide-insecticide treatments and dietholate in irrigated rice seeds

Abstract: The plant safener dietholate can be used for seed treatments (ST) to improve the selectivity of clomazone in rice cultures, thus allowing the application of higher dosages of this herbicide. The objective of this research was to evaluate the interaction between seed fungicide-insecticide treatments with and the plant safener dietholate in irrigated rice. Three experiments were carried out, and the first of them was conducted in a laboratory, following a completely randomized experimental design with four replications. Different ST and treatment-to-sowing intervals were evaluated. The second and third experiments were performed in field conditions, in a completely randomized block design with four replications. In experiment two, seeds were treated with different fungicides, in association or not with dietholate; while in experiment three, the effect of the ST with fungicides and dietholate with clomazone application were assessed. The results evidenced that the association between carboxin + thiram + dietholate reduced seed germination, vigor, and the dry mass of shoot of rice plants. The longer it takes between ST and sowing, the more rice seed germination is negatively affected. The association between fungicides and dietholate may have been antagonistic, and thus interfered with the culture growth potential.

Rice cultivation using plastic mulch under saturated moisture regime and its implications on weed management, water saving, productivity and profitability

A Rabi season (2012–13) field investigation was carried out at Directorate of Rice Research, Hyderabad to assess the impact of saturated moisture regime (SMR) with and without plastic mulching (black and transparent) in transplanted rice (TPR) on weed menace, water saving, productivity and economics as compared to 5 cm standing water regime (SWR) rice in RBD with six replications. Results revealed that no-mulch SMR rice has 37.3 and 80.2% higher weed count and thus 26.8 and 114.1% lower weed control efficiency than SWR rice culture at 20 and 40 days after transplanting. Plastic mulching (PM) with SMR has reduced the weed count and weed biomass in rice by over 90% as compared to no-mulch-SWR rice. Labour days required for weeding were enhanced by 50% under SMR (30 man days) as compared SWR (20 man days). SMR had 35% irrigation water (IW) economy but with 7.1% grain yield penalty (0.34 t/ha) as compared to SWR (100 cm IW use and 4.79 t/ha grain yield). When SMR was combined with plastic mulching (PM), there was aless yield depression (0.10–0.18 t/ha) when compared to SWR. SWR has more net returns (’ 42,160/ha) than SMR (’ 30,750). High cost of PM (’ 23,000/ha) with SMR has masked gains in IW, weeding costs saving and higher yields. SMR can be adopted without any challenges but weed management through PM is desired with added advantage of water economy. Reducing cost of plastic mulches and evolving biodegradable plastics may make SMR rice culture a reality.

Multifaceted Studies on Cooking Quality of Various Rice and Japanese Dietary Habits and Culture

Multifaceted Studies on Cooking Quality of Various Rice and Japanese Dietary Habits and Culture

Rice to Ruin: The Jonathan Lucas Family in South Carolina, 1783–1929 by Roy Williams III, Alexander Lucas Lofton

Reviewed by: Rice to Ruin: The Jonathan Lucas Family in South Carolina, 1783–1929 by Roy Williams III, Alexander Lucas Lofton James H. Tuten Rice to Ruin: The Jonathan Lucas Family in South Carolina, 1783–1929. By Roy Williams III and Alexander Lucas Lofton. (Columbia: University of South Carolina Press, 2018. Pp xii, 427. $59.99, ISBN 978-1-61117-834-0.) The rice planters of South Carolina do not suffer from lack of study. As a distinctive subset of southern planters, who had some of the highest ownership rates of enslaved people and who boasted some of the most luxurious lifestyles in the antebellum era, rice planters remain a source of interest for many. Even now, new collections of privately held papers become public and reveal even more about this group who influenced the lives of many. Rice to Ruin: The Jonathan Lucas Family in South Carolina, 1783–1929 adds to the library of work on the rice planter class by focusing on five generations of the Lucas family. The family built rice mills and eventually owned some of the most famous rice plantations in the Lowcountry, several of Charleston’s premier mansions, and upland homes, where they escaped malaria. The family’s rise to prominence came by chance, when a vessel carrying English millwright Jonathan Lucas wrecked on the South Carolina coast. He recognized that the area needed his mill-building knowledge. Growing rice can be challenging and has been historically difficult, but dehulling or milling rice can also be a slow and tedious process to perform at scale. Lucas innovated and designed a new water-powered mill for dehulling rice in the 1780s, making him “the Eli Whitney of the rice culture” (p. 6). Lucas’s designs removed the [End Page 891] major bottleneck to rice production, and his mill construction company, which employed his sons and grandson, constructed mills on numerous plantations and in Europe. They built a toll mill near Charleston, and Jonathan Lucas II built and operated the largest steam-powered rice mill in the old rice kingdom. The family used the profits from mill construction to buy rice plantations, securing its place in the insular rice baron society. The family engineered its own reversals by supporting secession and the Civil War, in which many members fought. Like their fellow planters, the Lucas family suffered losses due to emancipation, property destruction, lost opportunity costs of the war years, and the resulting steep decline in the value of their land. In the decades after Reconstruction, the family dispersed to towns around South Carolina, to California, and to New York. Those who remained on rice plantations hoped for capital infusions that proved illusory, such as investments driven by phosphate discoveries, which benefited some of their neighbors during that industry’s boom. The family members found themselves at sea economically, unable to comprehend in the last decades of the nineteenth century “why they were all so poor and yet so capable” (p. 260). Instead, they managed decline and joined another widespread trend: selling land to northern waterfowl hunters. The authors know Lowcountry history well. One is a descendant of the Lucas family and the caretaker of the rich and clearly voluminous family papers, which recently went to the South Carolina Historical Society. The letters provide clues about the mentality of the planter class, the rise and fall of rice culture, and the daily family life of the planter elite. The authors rely heavily on lengthy transcriptions of this cache of letters. The book draws on an antiquarian approach that pays close attention to the voices of the past. At times it reads like an edited collection of letters. In that vein, the book offers no overarching argument and provides context more than analysis. This characteristic is most glaring when the book presents the white male planter-class point of view without considering the perspectives of women, poor white people, or enslaved people. The authors offer no support for the Lost Cause, but the work rarely challenges or gives context for rice planters’ blinkered understanding of the world. James H. Tuten Juniata College Copyright © 2019 The Southern Historical Association

Screening of different rice cultures for their reaction to stem borers, Scirpophaga incertulas and Sesamia inferens

Screening of different rice cultures for their reaction to stem borers, <i>Scirpophaga incertulas</i> and <i>Sesamia inferens</i>

TNAU Rice CO 51 (IET 21605)-A high yielding short duration fine grain rice variety for Tamil Nadu

Early duration rice culture CB 06535,aderivative of the cross ADT 43 / RR 272 -1745wasreleased as TNAU Rice CO 51 during the year 2013 as an alternate variety to ADT 43 with 105 -110 days duration with additional desirable features like high yield, physiological efficiency and better adaptability. This culture with semi dwarf stature has efficient tillering capacity, long droopy panicles with highly acceptable plant characters and is a good replacement for the rice variety ADT 43 due to its high grain yield and pest and disease resistance. In the overall performance, the culture, CB 06 535 recorded a mean productivity of 6623 kg/ha in seven years of trials with 10.72 per cent increase over ADT 43. At Nallampalli, Dharmapuri district, the culture has recorded the highest yield of 11,377 kg/ha among the trials conducted, demonstrating the highest yield potential of this variety. The culture CB 06 535 is moderately resistant to blast, BPH and GLH under artificial condition. It produces medium slender white rice with intermediate amylose, soft gel consistency and moderate gelatinization temperature. It produces good quality cooked rice besides high milling and head rice recovery. CB 06 535 with higher yield, better pest and disease resistance and good cooking quality in comparison to the check ADT 43 is suitable for cultivation during Kar/ Kuruvai/Sornavari/Navaraiand the seasons / tracts wherever early maturing rice varieties are cultivated throughout Tamil Nadu.

Thidiazuron and Ethyl-trinexapac Affect Upland Rice Irrigated by Sprinkler Irrigation

Rice is a prominent crop in Brazil. Its cultivation predominates in flooded areas in the South region of the country. However, the upland rice grown in the Midwest Region is a viable option for a sustainable expansion in the country. It still results in a grain yield lower than that of flooded cultivation, and there are constant problems with crop lodging, especially in areas using sprinkler irrigation. Thus, new ways to increase grain yield and minimize upland rice lodging are critical. The objective of this study is to verify the effects of thidiazuron and ethyl-trinexapac on the rice culture and verify whether the simultaneous use of both results in a beneficial interaction. The work was carried out in Selv&amp;iacute;ria, MS, using the cultivar BRS Esmeralda in the agricultural years 2015/16 and 2017/18. The experimental design was randomized blocks in a 2 &amp;times; 4 factorial design with four replications. The treatments were combinations of application of the plant regulator thidiazuron at a fixed dose of 1.0 g ha-1 (presence or absence) and four doses of the growth regulator ethyl-trinexapac (0, 50, 100 and 150 g ha-1). Thidiazuron did not affect grains yield. Ethyl-trinexapac reduced plant height and eliminated lodging. The simultaneous use of both regulators did not affect the rice culture regarding the analyzed variables.

Application of biodegradable seedling trays in paddy fields: Impacts on the microbial community

Biodegradable plastics have been widely introduced into agricultural production, but their impacts on the soil ecosystem remain unclear. The present study investigated the impacts of a biodegradable seedling tray (BST) on the microbial communities in paddy soils. A 110-day rice culture experiment was conducted with three different paddy soils developed from black soil (BS, black chernozem soil), chao soil (CS, Fluvo-aquic) and red soil (RS, Alfisols) and three application rates of BST (0, 0.02 and 0.2 g kg−1). Soil phthalic acid ester (PAE) concentrations, physicochemical properties and enzyme activities were determined to evaluate the influence of BSTs on soil quality. 16S high-throughput sequencing was used to study bacterial community composition and the Biolog EcoPlate™ test was used to profile microbial activity and community function. Results show that the application of BSTs did not markedly affect soil quality, and the potential release of PAEs from BSTs was negligible. Interestingly, the microbial community was affected by BSTs in a soil-dependent and time-dependent pattern. The microbial community in RS was not significantly influenced by BSTs. Relative abundances of some predominant genera in BS (e.g. norank_f__BSV40) and CS (e.g. Norank_f__Nitrosomonadaceae) were significantly influenced by BSTs, and db-RDA results show that community composition in BS and CS was shaped mainly by BSTs. Community level profiling shows that BSTs significantly increased microbial activity and decreased functional diversity in BS after 55 days, but the impacts disappeared after 110 days. The results contribute to the knowledge of how biodegradable plastics influence microbial communities in paddy fields and provide information relevant to the practical use of BSTs under field condition.

Anther culture in rice proportionally rescues microspores according to gametophytic gene effect and enhances genetic study of hybrid sterility

BackgroundTo investigate plant hybrid sterility, we studied interspecific hybrids of two cultivated rice species, Asian rice (Oryza sativa) and African rice (O. glaberrima). Male gametes of these hybrids display complete sterility owing to a dozen of hybrid sterility loci, termed HS loci, but this complicated genetic system remains poorly understood.ResultsMicrospores from these interspecific hybrids form sterile pollen but are viable at the immature stage. Application of the anther culture (AC) method caused these immature microspores to induce callus. The segregation distortion of 11 among 13 known HS loci was assessed in the callus population. Using many individual calli, fine mapping of the HS loci was attempted based on heterozygotes produced from chromosome segment substitution lines (CSSLs). Transmission ratio distortion (TRD) from microspores was detected at 6 of 11 HS loci in the callus population. The fine mapping of S1 and S19 loci using CSSLs revealed precise distances of markers from the positions of HS loci exhibiting excessive TRD.ConclusionsWe demonstrated that AC to generate callus populations derived from immature microspores is a useful methodology for genetic study. The callus population facilitated detection of TRD at multiple HS loci and dramatically shortened the process for mapping hybrid sterility genes.

Marasas et al. 1984 “Toxigenic Fusarium Species: Identity and Mycotoxicology” revisited

ABSTRACTThis study was conducted to determine the species identity and mycotoxin potential of 158 Fusarium strains originally archived in the South African Medical Research Council’s Mycotoxigenic Fungal Collection (MRC) that were reported to comprise 17 morphologically distinct species in the classic 1984 compilation by Marasas et al., Toxigenic Fusarium Species: Identity and Mycotoxicology. Maximum likelihood and maximum parsimony molecular phylogenetic analyses of single and multilocus DNA sequence data indicated that the strains represented 46 genealogically exclusive phylogenetically distinct species distributed among eight species complexes. Moreover, the phylogenetic data revealed that 80/158 strains were received under a name that is not accepted today (ex F. moniliforme) or classified under a different species name. In addition, gas chromatography–mass spectrometry (GC-MS) and/or high-performance liquid chromatography–mass spectrometry (HPLC-MS)-based mycotoxin analyses were conducted to determine which toxins the strains could produce in liquid and/or solid cultures. All of the trichothecene toxin–producing fusaria were nested within the F. sambucinum (FSAMSC) or F. incarnatum-equiseti (FIESC) species complexes. Consistent with this finding, GC-MS analyses detected trichothecenes in agmatine-containing broth or rice culture extracts of all 13 FSAMSC and 10/12 FIESC species tested. Species in six and seven of the eight species complexes were able to produce moniliformin and beauvericin, respectively, whereas B-type fumonisins were only detected in extracts of cracked maize kernel cultures of three species in the F. fujikuroi (FFSC) species complex.

Metabolites from endophytic fungus; Pestalotiopsis clavispora isolated from Phoenix reclinata leaf

Three secondary metabolites; dihydroxanthenone AGI-B4, syndowinin B and pitholide B were isolated for the first time from the ethyl acetate extract of the solid rice cultures of Pestalotiopsis clavispora, isolated from Phoenix reclinata Jacq. Family, Arecaceae collected in Nigeria.

Ecological Studies of Odonata Population in Northern Sumatra, Indonesia

Odonata is importants insect groups in the world. Ten ha rice field plot in three sites in Manik Rambung Rice Field (MRRF), Simalungun District, North of Sumatera (latitude: 2°53‘ 52.8"N and longitude: 99° 00‘24.4"E, about 90 km from Medan City at 594 - 602 masl) were recorded of Odonata population. The farmers have rice culture practices, combine with fish farming during season paddy planting. The comparison was conducted which nine stations of green Campus areas with purpossive randomsampling in a month (November, 1. 2011 until November, 28. 2011) using sweep net (400 μm mesh, 60cm x 90cm) which six swings started from 0900 to 1200 for collection of Odonata. The results were collected 445 individuals from sub-order Zygopteran and 892 individuals from sub order Anisoperan, 3 families, and 19 species of adults Odonata were identified IN MRRF. Family Coenagrionidae (Zygoptera) were dominant by Agriocnemis femina, A. pygmaea, and Ischnura senegalensis. Only Ictinogomphus decoratus recorded fromGomphidae and 11 species from Libellulidae. While two sub order, 4 families, 26 genera, 31 species and 436 individuals of Odonata identified in green campus, USU, Sumatera Utara, Indonesia. In MRRF, the ecological indices were calculated with score H‘ (0.88 - 2.50), Index Simpson (1-D) recorded were 0.49 until 0.99, while index Jaccard with 0.60-1.00. While Diversities indices Shannon and Evenness Pilou of Odonata in Campus USU was lower recorded in Station 7 and Station 1, while the highest were collected in Station 3 and Station 6. The diversities and evenness Odonata species were varied (H‘=2.20-3.42 and E=0.55-0.78). Comparison to the eveness and richness of Odonata species in each stations were differences, which effected by natural habitat, heterogenous vegetations of plants, time and weather while taken sampling, biotic, physics, and chemicals factors in environmental system are varied.

A new depsidone derivative from mangrove sediment derived fungus Lasiodiplodia theobromae

A new depsidone derivative botryorhodine I (1), along with eight known compounds (2-9) were obtained from solid rice cultures of the fungal strain, Lasiodiplodia theobromae M4.2-2 isolated from a mangrove sediment sample. The structures of the isolated compounds were elucidated on the basis of 1 D and 2 D NMR analysis as well as by HRESIMS. All compounds were evaluated for their cytotoxic potential against the mouse lymphoma cell line L5178Y as well as for their antibacterial activities against a panel of Gram-positive and Gram-negative bacterial strains. Compound 3 revealed potent cytotoxic activity with an IC50 of 7.3 µM whereas compound 7 showed selective anti-bacterial activity against different S. aureus and E. faecium bacterial strains with MIC value of 25 µg/ml.

Molecular Characterization, Fitness, and Mycotoxin Production of Fusarium asiaticum Strains Resistant to Fludioxonil.

Fludioxonil is used in seedborne disease management of various fungal pathogens, including Fusarium asiaticum, the predominant causal agent of Fusarium head blight in China. In this study, we screened resistant strains from a large number of F. asiaticum strains collected from 2012 to 2016 and found that 4 of 1,000 field strains were highly resistant to fludioxonil. The 50% effective concentration values of the resistant strains and induced mutants ranged from 80 to >400 μg/ml. Compared with field-sensitive strains, all field-collected and laboratory-induced resistant strains exhibited fitness defects in traits including mycelial growth, conidial production, pathogenicity, and sensitivity to osmotic conditions. In the presence of fludioxonil, significantly higher glycerol accumulation was found in sensitive strains but not in resistant individuals. The fludioxonil-resistant strains produced lower amounts of glycerol in liquid culture and lower amounts of trichothecene mycotoxins in rice culture and inoculated wheat spikelets than the fludioxonil-sensitive strains. Sequence analyses of the key genes of the two-component histidine kinase signaling pathway showed various amino acid substitutions in the Os1, Os4, and Os5 genes between field-sensitive and resistant strains or mutants. The results of this study suggest a potential risk of fludioxonil resistance development and a possible influence of resistance mutations on fitness parameters and toxin production in F. asiaticum.

Cross-Resistance to Imazapic and Imazapyr in a Weedy Rice (Oryza sativa) Biotype Found in Malaysia

ABSTRACT: The Clearfield® rice production system is an effective management tool for weedy rice and other weeds in the direct-seeded rice culture. However, if farmers cultivating the Clearfield® rice disregard stewardship recommendations, the industry could face a problem of herbicide-resistant weedy rice which would occur through the selection of outcrosses. This study aimed to confirm imidazolinone-resistant weedy rice in Malaysia. The resistant weedy rice (R-WR) was found to be 67 fold more resistant to OnDuty® (premix of imazapic and imazapyr) than the susceptible weedy rice (S-WR) based on the GR50 values (rate that causes 50% inhibition of shoot growth). The Clearfield® rice cultivar was 32-fold more tolerant to OnDuty® than the S-WR. Furthermore, the R-WR was 54 and 89 fold more resistant to imazapic and imazapyr applied separately than the S-WR, respectively. The Clearfield® rice was 140- and 40-fold more tolerant to imazapic and imazapyr, respectively than the S-WR. The R-WR biotype was susceptible to non-selective herbicides glyphosate and glufosinate, as well as the selective graminicide quizalofop. Oxadiazon controlled the R-WR biotype, but pretilachlor was ineffective. The present study documented the first case of weedy rice that was cross-resistant to imazapic and imazapyr in Malaysian Clearfield® rice field.

The Effects of Crop Establishment Method, Soil–Water Regime and Integrated Nutrient Management Practices on Sustainability of Rice Yield in North-Eastern India

A field experiment was conducted in rice fields of the mid-tropical plain zone of north-eastern India with an aim to develop options through integrated management of soil, water, nutrition and plant for sustainable rice production. The experimental fields were managed in three transects by growing rice under the system of rice intensification (SRI), integrated crop management (ICM) and conventional rice culture (CRC) with fertiliser treatments of NPK100–100–100; NPK100–100–100 + FYM; and NPK50–50–50 + FYM + biofertiliser. The results reveal that the SRI and ICM systems of rice culture give a good yield with better water use efficiency. The quantity of water required for producing one kilogram of rice was 1498 L in SRI and 1535 L in ICM compared to 1883 L in CRC. The requirement of fertiliser under SRI and ICM methods of transplanted rice was less than half of the fertiliser requirement of the CRC method. The soil–water regime, crop establishment method and integrated nutrient management (INM) practices significantly influenced the sustainability yield indices (85–99%) of rice in this climate scenario.

Effect of Pre-Soaking on Seedling Establishment and Pretilachlor Tolerance in Four Rice Genotypes

This study aimed to investigate the effects of pre-soaking for 2 h before seeding on rice seedling establishment after 15-day spraying with pretilachlor. The cytochrome P-450 content, glutathione S-transferase (GSTs), and root activity were also determined. Seedlings of four rice cultivars with contrasting tolerance of pretilachlor were compared. Seed pre-treatment by pre-soaking increased the survivability and growth under pretilachlor spray and improved seedling establishment by increasing P-450, GSTs and root activities. Tolerant genotypes, super hybrid rice, responded better to pre-soaking in direct-seeded rice treated with pretilachlor. It is important for establishment in direct-seeded rice with pre-soaking seeds before sowing in improving emergence and seedling. The positive effect of pre-soaking was proved in all four rice genotypes. Seed pre-soaking will be effective in direct-seeded rice culture to protect rice treated with pre-emergence herbicide and control weedy rice.

Analysing Dry-Seeded Rice Responses to Planting Time and Irrigation Regimes in a Subtropical Environment Using ORYZA2000 Model

Irrigated rice is a luxurious consumer of water. Dry-seeded rice culture is an option that saves water, but may entail loss in crop yield implying a trade-off of productivity and water conservation. This study evaluates the water balance and productivity response of dry-seeded rice to management interventions using ORYZA2000 model. The database was generated from field studies involving combinations of planting dates and irrigation regimes. The performance of the model in simulating phenology, biomass, water use and yield was reasonable within the experimental conditions. The normalized root mean square of deviation (RMSDn) for simulated and measured harvest-time biomass and grain yield was 12 and 16%, while RMSDn for progressive soil water content and water use was less than 10%. Scenario analysis using historical weather data showed that rice planted on June 16 had minimum variance in potential yield (5.4%) compared to earlier (June 1) or later (July 1) planting. The evapotranspiration (ET)-based water productivity (WPET) was greater for June 16 and July 1 than June 1 planting. Loss of yield and WPET with reduction in irrigation frequency were least on June 16 rice implying this as optimal planting time of rice in the study region.