Additional insights into the adaptation of cotton plants under abiotic stresses by in silico analysis of conserved miRNAs in cotton expressed sequence tag database (dbEST)

Abiotic stress is the primary cause of crop losses worldwide. In addition to protein coding genes, microRNAs (miRNAs) have emerged as important players in plant stress responses. Though miRNAs are key in regulating many aspects of plant developmental plasticity under abiotic stresses, very few information are available in cotton. Hence, this study was conducted to identify the phylogenetically conserved miRNAs in cotton, using computational approaches. In this paper, we reported a set of miRNAs such as miR159, miR165, miR170, miR319, miR529, miR828, miR869, miR1030, miR1884, and miR2118 that are likely to be involved in abiotic stress response. Although, few of them have been described in literature for their specific role in fiber development, literature survey have shown that they may also be involved in abiotic stress response. Interestingly, miRNAs reported in this study were found to have several targets that are involved in abiotic stress resistance. Considering all together, it was concluded that these newly identified conserved microRNAs in cotton have great potential in future efforts to improve abiotic stress tolerance in cotton.Key words: miRNA, cotton, abiotic stress resistance, in silico analysis

Marker-Assisted Breeding as Next-Generation Strategy for Genetic Improvement of Productivity and Quality: Can It Be Realized in Cotton?

The dawdling development in genetic improvement of cotton with conventional breeding program is chiefly due to lack of complete knowledge on and precise manipulation of fiber productivity and quality. Naturally available cotton continues to be a resource for the upcoming breeding program, and contemporary technologies to exploit the available natural variation are outlined in this paper for further improvement of fiber. Particularly emphasis is given to application, obstacles, and perspectives of marker-assisted breeding since it appears to be more promising in manipulating novel genes that are available in the cotton germplasm. Deployment of system quantitative genetics in marker-assisted breeding program would be essential to realize its role in cotton. At the same time, role of genetic engineering and in vitro mutagenesis cannot be ruled out in genetic improvement of cotton

Phenotypic and genotype analysis of drought-resistance traits for developement of rice cultivars adapted to rainfed environments

Many of the world's rice-growing regions lack adequate irrigation facilities, and drought frequently reduces yield. This paper reviews drought-resistance traits in rice and their quantitative trait loci (QTLs), with emphasis on CT9993/IR62266, one of the most widely studied mapping populations, and suggests ways to develop cultivars that will perform well in drought-prone environments. Information about the type of drought faced in the target region - particularly the timing of the drought (late season terminal drought, early stage vegetative drought, and intermittent drought) and the intensity of the drought - are important in determining the specific plant traits required to improve drought resistance in rice. Most of these traits are related to drought avoidance strategy, so that the drought-resistant genotypes are able to maintain better internal water status, either by taking up more water through a better root system or by reducing the rate of plant water use. We identified and listed a number of QTLs for many drought-resistance traits, such as deep roots. We identified four key genomic regions on chromosomes 1, 4, 8, and 9 on which are co-located a number of QTLs for traits considered to be directly or indirectly responsible for grain yield under stress. These regions, once they have been more finely mapped, appear promising for eventual use in marker-assisted selection for development of drought-resistant rice varieties. In addition to selecting for specific traits or specific genomic regions, screening under managed drought conditions on the basis of yield itself or on spikelet fertility adjusted for flowering time appears useful, because of the relatively high degrees of heritability of these characters, for the development of drought-resistant rice cultivars, and it is currently practiced in some breeding programs

Identification of Contrasting Parents and Development of Mapping Population for Sucking Pest Resistance in Cotton

The current study was conducted to identify the best parents with good agronomical features and contrasting characteristics for sucking pest resistance to develop a population that can be used for Quantitative Trait Loci mapping of resistance component traits. Initial attempts at this university have enabled to identify of five potential parents (viz., KC3, NDLH 1938, CO18, K12, and RG8) with improved sucking pest resistance and yield characters and they were crossed with the recently released high-yielding variety CO-17, which is also suitable for high-density planting.  All these six parents were evaluated for fiber yield and quality traits besides anatomical characters such as trichomes density, length, width, and sharpness that confers sucking pest resistance and genotyped with 200 Simple Sequence Repeats markers that span the entire genome. Efforts have been dedicated to the careful selection of optimal parents, namely CO17 and KC3, each possessing distinct traits related to resistance against sucking pests and also fiber quality characters in addition. This strategic approach aims to combine their contrasting genetic components for sucking pest resistance, to develop a new generation of plants that exhibit heightened resilience to these types of pests. CIR139, a polymorphic SSR marker of these two parents was used to fix the true hybrids which were advanced to generate an F2 mapping population.  This population is believed to be useful for QTL mapping of anatomical features that confer sucking pest resistance such as trichome length, density, breadth, and sharpness besides fiber yield and quality traits

Evaluation of Interspecific Hybrids for Yield and Quality Characteristics in Bitter Gourd (Momordica charantia L.)

Bitter gourd (Momordica charantia ) is one of the most nutritional and commercially important vegetable crops of the family cucurbitaceae. In the present study, hybrids and parents of bitter gourd were assessed to study the per se performance for yield and quality attributes. A wide range of significant variation was observed among all parents and hybrids under study. Among the parents assessed, Preethi and CO-1 was found highly significant with regard to yield attributing characters viz., fruit weight, fruit yield per plant, fruit yield ha-1 and MCM-1, MCM-2 with regard to number of fruits per plant. The hybrids CO-1 x MCM-2 followed by Preethi x MCM-1 and MCM-1 x Preethi were recorded to be the top performing hybrids for all the quantitative characters like node of first female flower appearance, days taken to first flower appearance, days to 50% flowering, fruit length(cm), fruit girth(cm), fruit weight(g),  internodal length(cm), vine length(cm), sex ratio, No of seeds per fruit, No. of fruits per plant, No. of harvest and yield per plant.  High ascorbic acid and iron content was recorded in parents MCM-2 and Preethi while it was found maximum in hybrids, Preethi x MCM-1, CO-1 x MCM-2 and MCM-1 X Preethi. Hence based on performance of yield and quality, the hybrids, CO-1 x MCM-2, Preethi x MCM-1 and MCM-1 x Preethi were found to be superior and can be exploited for further studies

Field Evaluation of Biorationals and Chemical Insecticides against Thrips parvispinus (Karny) (Thysanoptera: Thripidae), in Chrysanthemum

Field study was conducted to evaluate the efficacy of biorationals and chemical insecticides against black thrips, Thrips parvispinus (Karny) on chrysanthemum. Thrips population ranged from 15.33 to 13.89/flower before spraying. The efficacy of seven biorationals and seven chemical insecticides were evaluated against black thrips under field conditions. The application of pongamia soap @5g/lit and Spinosad 45% SC @ 0.2 ml/lit reduced the thrips incidence significantly among the biorational and chemical insecticides respectively. The mean per reduction of thrips incidence in pongamia soap @ 5 gm/lit application was 74.90%. This was followed by neem soap @ 5g/lit (72.25%), azadirachtin @10000ppm (71.10%), Beauveria bassiana (66.76%), Isaria fumosorosea (64.93%), Lecanicillium lecanii (63.72%), and Metarhizium anisopilae (62.46%). Among the chemical insecticides Spinosad 45%SC @ 0.2 ml/lt. stood first in the order of efficacy with 80.2% reduction in thrips population. The order of efficacy of chemical insecticides against black thrips in chrysanthemum are spinetoram 11.7%SC (76.245%) > cyantraniliprole 10%OD (73.92%) > fipronil 5% SC (72.24%) > thiamethoxam 25% WG (70.79%) > dinotefuran 20% WG (69.80%) > tolfenpyrad 15% EC (68.02%). The effective biorational and chemical insecticide can be included as a component in the Integrated pest management of thrips complex in chrysanthemum. The rotation of effective compounds will reduce the resistance development against insecticides in thrips associated with chrysanthemum and also reduces the thrips infestation

Evaluation of Tabernaemontana divaricata Accessions for Loose Flower Production

Crepe jasmine or East Indian rosebay or pinwheel flower, Tabernaemontana divaricata originated from India is a popular large shrub or a small tree grown in tropical and sub-tropical gardens for its beautiful glossy foliage and mild fragrant waxy white, ornamental flowers. It produces flowers throughout the year, except in winter but profusely during summer season. Rather than the opened flowers, the unopened flower buds are commonly used as an alternate to Jasminum sambac buds in off-season. The present investigation was carried out at the Department of Floriculture and Landscape Architecture, Horticulture college and Research Institute, Tamil Nadu agriculture university, Coimbatore during 2022-2023. Randomized Block Design was used with three replications with the objective of investigating promising genotypes of Tabernaemontana divaricata, collected based on the type of petals from different locations for loose flower production.  In the study totally 12 accessions were collected and named from Acc. No. 1 to 12. They are evaluated for their vegetative and floral parameters such as plant height, leaf length, leaf width, no. of branches, plant spread in EW & NS direction. Floral parameters include bud length, bud diameter, stalk length and no. of petals/flower. Out of the collected accessions, Acc. No. 2 & 5 are suitable for veni arrangement and Acc. No.10 & 11 are suitable for garland making. Buds of acc. No.4 & 6 are similar to Jasminum sambac and J. auriculatum buds

Biological Preparation, Characterization of CaO Nanoparticles from Egg Shell Waste and Insecticidal Activity against Seed Weevil, Sitophilus oryzae L. in Maize

Calcium oxide (CaO) nanoparticles was biologically synthesized by calcinating egg shells from kitchen waste and characterized using SEM, UV-Vis, XRD and FT-IR. Biosynthesized CaO nanoparticles are found to be an effective insecticide against seed weevil, Sitophilus oryzae in maize. The indiscriminate use of already available commercial pesticides has led to develop resistance among the pests and also occurrence of pesticide residues in produce. The SEM study revealed that the particles are granular in shape with a size of 189 nm.  The diffraction peaks of XRD were observed at 2θ = 32.320, 37.48°, 48.40°, 53.96°, 64.18°, 67.52°and exhibited polycrystalline nature.  In the FTIR spectrum, a broad band at 1410 cm-1, a sign of a C-O bond which indicated the association between the oxygen atom of carbonate and the calcium atom. The insecticidal activity of CaO nanoparticles was assessed against S. oryzae by contact toxicity bioassay method. The outcomes of the bioassay studies showed that the lethal dose (LD50) for maize seeds was 72.62 mg/100 g. and within seven days of exposure, 100% death of S. oryzae was attained at a dosage of 240 mg/100 gm of maize seeds. The current study concluded that biosynthesized CaO nanoparticles may be used as an effective management technique to successfully manage the S. oryzae under storage conditions as an alternative to chemical pesticides