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A drought-resistant plant with high adaptability to various climatic and soil conditions is castor (Ricinus communis L.). There is currently a significant expectation of increased castor oil demand on the global market. When it comes to crop development, there are a variety of factors to take into account for each growing region, especially when it is preferable to fit the castor crop to specific tillage practices and intercropping system. In this veneration, the current study's goal was to determine the effects of various tillage methods and legume crop-based intercropping system in rainfed regions. The field experiments were conducted in 2021-2022 and 2022-2023 at Tapioca and Castor Research Station, Tamil Nadu Agricultural University, Yethapur. The experimental treatments consisted of conventional tillage and minimum tillage as main plot and castor based inter cropping system @ 1:3 ratio viz., Castor + Greengram, Castor + Cowpea, Castor + Groundnut and Sole Castor as subplot treatments and conducted in split plot design with three replications. The pooled results of a two-year study of different tillage practices in legume crop based intercropping systems in rainfed conditions showed no significant difference among tillage practices relevant to growth, yield attributing characters, seed yield and biomass yield, however higher values were registered under conventional tillage practices over minimum tillage. Higher seed yield of both base (1152 kg ha-1) and inter crop (481 kg ha-1) were documented in conventional tillage practices over minimum tillage. With respect to inter cropping, higher base crop (castor) yield of 1058 kg ha-1 was recorded under castor + groundnut inter cropping system, which was observed to be on par with sole castor (1020 kg ha-1), and castor + greengram (907 kg ha-1). Recorded highest Castor equivalent yield in castor + groundnut (1:3) intercropping, grown under a conventional tillage system. Moreover, the maximum benefit-cost ratio was recorded in castor + groundnut (1:3) intercropping, over sole castor cropping. The highest Castor Equivalent Yield (CEY) in a conventional tillage system was observed in a castor + groundnut (1:3) intercropping system. [ABSTRACT FROM AUTHOR]

Nerium is a versatile flowering plant requiring less labor and low input for commercial cultivations. The growers harvest the mature flower buds from late at night to early in the morning hours with the use of a headlight as the flowers exhibit full bloom in the morning. With this background, investigation was done under different conditions of lighting and water spraying in the form of fog in nerium variety 'pink' at Samakuttapatti village, Panamarathupatti Block, Salem district, Tamil Nadu, India. The plant height (268.00 cm) was maximum in the plants exposed with 450-495 nm of blue light for 6 h + water spray (fog) 15 min. for every 1 h. Inflorescence with the highest number of flower buds (9.25) and flower yield (230.80 g plant-1) were recorded in water spray (Fog) 15 min. for every 1 h which highly favored for harvesting between 5.30 A.M. and 7.30 A.M. or preferably in the previous day evening. The same treatment exerted the highest benefit cost ratio (2.83). The Principal Component analysis showed strong association with Percentage of unopened flower buds (POUP), Single flower bud weight (SFBW), Number of flower buds per inflorescence (NFB) and Total number of inflorescence plant-1. [ABSTRACT FROM AUTHOR]

The estimates of combining ability and nature of gene action were worked out by Line x Tester analysis (Kempthorne, 1957). The experimental material included 45 entries containing six pistillate lines (DPC 9, DPC 21, D PC 24, YRCP 1, YRCP 2 and JP 65), five monoecious lines (TMV 5, SKI 215, 48-1, M3/28-3-1, and JM 6), thirty cross combinations, and four standard checks (YRCH 1, YRCH 2, ICH 66, and YTP 1). Four hybrids (DPC 9 x M3/28-3-1, DPC 9 x TMV 5, JP 65 x M3/28-3-1 and JP 65 x 48-1) exhibited high and significant positive economic heterosis for seed yield. The combining ability analysis demonstrated that the mean sum of squares due to genotypes and crosses were significant for all yield and its contributing traits. The magnitude of genetic variances for 11 quantitative traits revealed the predominance of dominant gene action for all the traits except oil content and hundred seed weight. For most traits, testers contributed more to total variance than the lines and L x T interaction. DPC 9, DPC 24, TMV 5, and JP 65 were identified to be the best general combiners for seed yield and its yield components. The hybrids DPC 9 x M3/28-3-1, DPC 9 x TMV 5, JP 65 x M3/28-3-1, and JP 65 x 48-1 were the most effective specific combiners for seed yield and also exhibited significant and high standard heterosis in the desired direction for seed yield and majority of the yield contributing traits. Hence, these parents and cross combinations could be effectively utilized for development of high yielding castor hybrids [ABSTRACT FROM AUTHOR]

Diverse source of early genotypes is obligatory for breeding high yielding early castor (Ricinus communis L.) cultivars. One hundred and twenty-five medium duration genotypes including three checks were evaluated for the presence of genetic diversity and variability. Genetic distance, variance components and correlation coefficients were estimated for seven seed related quantitative traits. Significant genotypic differences were observed among the collections for these traits. High heritability and high genetic advance were noticed for seed length, seed breadth, Length/Breadth ratio, shelling percentage, 100 seed weight and seed yield per plant, thus mode of gene action reported was additive. Genetic diversity analysis based on dendrogram, phenogram and circular form grouped the entries into seven groups and it computed inter and intra cluster distance. Principal Component Analysis (PCA) revealed that the first three components cumulatively accounted for 72.57 per cent of the total variation. Seed yield per plant showed a significant association with shelling percentage and 100 seed weight. Also, direct effects were high and positive through seed breadth, Length/Breadth ratio and 100 seed weight. The promising genotypes identified (ICIRG 2272103 and RG 1673) and the information generated would be useful for breeding early/medium cultivars as well to understand the physiological mechanism related to earliness in castor. [ABSTRACT FROM AUTHOR]

It is axiomatic that castor (Ricinus communis L.) is an industrially important oil crop with wide use. Though it is possible to augment oil yield by selecting appropriate parental lines, seed yield of the parents should also be given due weightage to meet out the increasing oil demand. Hence, it is imperative to improve the seed yield by breeding elite hybrids/varieties. Morphological description of 208 castor genotypic population for eight qualitative traits was carried out and considerable polymorphism existed among the collection. Maximum genotypes were R2 and R3 morphotypes because of the dominant nature of red stem color and blooming nature. K means clustering separated the genotypes into 20 clusters with cluster 4 and 20 as well separated ones. Cluster 4 could serve as female parent since the cluster was composed of pistillate lines and cluster 20 as male parent during hybridization. Path coefficient analysis supported the correlation coefficient that effective spike length and capsule weight showed high positive direct effects with seed yield. Also, the analysis revealed primary spike length and effective length of primary spike as the variables with the largest weightage. The first four components accounted for 75.95% of the variation cumulatively. The components were rotated with varimax rotation and the variability contribution was similar to the normal (76%). High communality values specified the reliability of the studied variables in explaining the total variation. Considering both cluster analysis and PCA, the genotypes SKP 84, DPC 19, JP 65, JC 3, JC 26, RG 27, ICS 210 and RG 3477 possessed superior agronomic performance. Hence, these genotypes/germplasms had immense value as parents in breeding varieties/hybrids to meet out the global oil demand. [ABSTRACT FROM AUTHOR]

Castor is an important industrial oilseed crop utilized for multivarious applications. Augmenting seed yield in long duration castor varieties is of utmost importance to meet the increasing oil demand and also to make them suitable for inter/border cropping. Understanding the genetic diversity in base population of monoecious lines and interrelationship between economic traits are very much important to formulate suitable genetic improvement programmes. In this regard, seed morphological characterization and genetic diversity was assessed in 62 late flowering monoecious lines. Predominance of brown colour, ellipsoid shape and conspicuous mottling with caruncle was observed among the genotypes. Cluster analysis grouped them into eight different clusters. Maximum inter cluster distance was found between cluster VI and VIII, whereas intra cluster distance was high in cluster II. Cluster VI recorded the highest cluster mean for 100 seed weight and seed yield per plant (44.56 g and 174 g, respectively). Association studies revealed 100 seed weight and shelling percentage to be the significant traits for indirect selection of yield. In conclusion, the cluster VI has potential genotypes to utilize in developing high yielding varieties and male parent donor for hybrid breeding. The diverse genotypes identified from this study could be given priority during recombination breeding to get diverse segregants and for further molecular analysis like mapping population development and QTL/gene identification. [ABSTRACT FROM AUTHOR]

Castor is one of the non - edible oilseed crop cultivated all over the world. Knowledge on genetic divergence is the foremost important tool for the initiation of any successful breeding programme. The present investigation aims to reveals the nature and magnitude of diversity that exist among the 70 castor genotypes based on 11 biometrical traits, using Mahalanobis D2 statistics. Based on the genetic distance, 70 castor genotypes were grouped into seven different clusters. Among the characters studied, seed yield per plant (45.96 per cent) had major contribution to the total divergence. The maximum interclusters distance was recorded between genotypes cluster IV and cluster VI. The maximum interacluster distance was observed in the cluster VII (28.28). Thus, selection of genotypes from diverse clusters for future hybridization programme as a parental genotypes will helps to obtain segregants. [ABSTRACT FROM AUTHOR]