The concerned research aimed to investigate the peculiarities of adaptation to water regime and photosynthetic activity in four dye-yielding plant species (Indigofera tinctoria L., Rubia tinctorum L., Isatis tinctoria L., and Lawsonia inermis L.) cultivated in the Surkhandarya Region, Uzbekistan. During the study, the leaf cell sap (LCS) concentration and content of the key photosynthetic pigments, such as chlorophylls a and b, total pigment concentration, and carotenoids, succeeded in their determination at the budding stage under normal and water-deficit conditions. The obtained results allowed for identifying the degree of osmotic adaptation and photoadaptation mechanisms of the plants under water-deficit conditions. The results lay down a scientific base for assessing the ecological stability of dye-yielding plants and determining cultivars resistant to water stress conditions with increasing photosynthetic efficiency. Detecting the chlorophylls a and b and carotenoid contents in leaf samples used the spectrophotometric method. The results revealed a considerable decline in photosynthetic pigments’ concentration under water-deficit conditions; however, these also showed robust adaptive processes in certain species (especially the species Indigofera tinctoria L.). Biochemical analysis disclosed an increase in the anthocyanin and flavonoid contents, ensuring stress tolerance in dye-yielding plants. This approach helps in distinguishing the degree of plant adaptability with enhanced efficiency in natural pigments’ production.

Keywords: Dye-yielding plants, natural dye, species, physiology, photosynthetic pigments, chlorophyll a and b, carotenoid, cell sap, water-deficit conditions

Key findings: The dye-yielding plant species (Indigofera tinctoria L., Rubia tinctorum L., Isatis tinctoria L., and Lawsonia inermis L.) exhibited distinct physiological responses to water-deficit conditions. The species Rubia tinctorum L. and Lawsonia inermis L. showed higher cell sap concentrations, suggesting a considerable capacity for drought adaptation.

Salinity is one of the major abiotic stresses that considerably and adversely affects cotton growth, development, and seed cotton yield. The relevant study aimed to analyze regression and correlation among the morphological traits of 12 cotton (Gossypium hirsutum L.) cultivars exposed to different concentrations of sodium chloride (NaCl). Four levels of NaCl stress (0, 100, 150, and 200 mM) were successful in their application under controlled conditions. The results revealed different levels of salt stress conditions negatively influence cotton traits, particularly the fresh plant weight and shoot length, which showed a decrease of about 50% and 29%, respectively. The dry root weight and root length demonstrated a high degree of stability under salt stress conditions. According to the correlation analysis, plant length and root length appeared as positively correlated with other traits under different mM of NaCl stress conditions. These findings provide useful insights for identifying salt-tolerant cotton genotypes through marker-assisted selection and physiological screening.

Keywords: Correlation, salt stress, ions, SNP markers, SSR, cotton cultivar

Key findings: The regression value of plant length against other cotton (G. hirsutum L.) traits, as calculated, enabled the probabilistic estimation of those traits. The considerable positive correlations were evident among the assessed phenotypic traits under different salt stress conditions. The study identified the most susceptible and tolerant cotton traits.

Coconut (Cocos nucifera L.) cultivation prevails in over 90 tropical countries. Dwarf coconut varieties from Asia-Pacific are prominent for their short stature, early flowering, and high yield. In Malaysia, coconut ranks as the fourth most important crop, yet production comes behind the demand due to rising industrial and household use. Improving dwarf cultivars is crucial to enhancing productivity and reducing imports. This study analyzed genotypic variability in three Malaysian recommended dwarf cultivars—Malayan Yellow Dwarf, Malayan Red Dwarf, and Pandan—to identify genotypes suitable for further development. Ninety mature palms (30 per cultivar) succeeded in their assessment for 10 phenotypic traits per palm. Such traits were nut yield (number of nuts per palm per year), palm height, girth at 20 cm and 150 cm aboveground levels, the number of female flowers, spadix length, largest unopened spathe length, the number of unopened spathes, length of 11 leaf scars, and the number of rachillas. The restricted maximum likelihood (REML) and best linear unbiased prediction (BLUP) were methods used to estimate variance components, and the multi-trait genotype-ideotype distance index (MGIDI) enabled the multi-trait selection. Significant genotypic variability was evident among coconut genotypes, with heritabilities at 69%–99% and repeatabilities at 68%–100%. Cluster and principal component analyses (PCA) distinguished the Pandan cultivar from MYD and MRD. PCA explained 83.5% of the variation (PC1: 40.8%; PC2: 18.9%), with the yield, palm height, and girth loading comprising PC1 and spathe and spadix lengths on PC2. The MGIDI identified four superior genotypes per cultivar, with yield gains up to 67% in MRD, 59% in MYD, and 34% in Pandan.

Keywords: Dwarf coconut (C. nucifera L.) cultivars, inter and intra population variability, phenotypic traits, REML, BLUP, MGIDI, Cluster and PCA, yield gain

Key findings: The study revealed significant genetic variability within and among three dwarf coconut (C. nucifera L.) cultivars, with the highest heritability and repeatability supporting effective selection. Yield, palm height, and girth were the main traits driving genetic variability and offering practical targets for further improvement in coconut yield.

Genetic variability and trait relationships were evaluated in 15 improved cultivars of Southern Thai indigenous rice (Oryza sativa L.). The study focused on grain yield and quality-related traits to reinforce rice breeding initiatives. Significant genetic variability was evident among the rice genotypes, with substantial genotypic and phenotypic coefficients of variation for the number of tillers and the number of ears, along with high heritability estimates for these traits. These indicate a robust genetic control and suitability for selection. Path coefficient analysis identified the number of tillers and the number of ears as primary contributors to seed weight per panicle. Protein content exhibited a complex relationship, receiving negative influences from seed weight per panicle and the number of seeds, suggesting their importance for improvement in grain yield. Correlation analysis revealed a considerable positive association between the number of tillers and the number of ears; however, a negative correlation between seed weight per panicle and protein content indicates a challenge in simultaneously improving both traits in rice. Principal component analysis confirmed seed weight per panicle and protein content were the primary drivers of the variability. The results will enable breeders to optimize grain yield and quality and develop high-yielding and nutritious rice cultivars for sustainable production.

Keywords: Rice (O. sativa L.), improved cultivars, genetic variability, path analysis, correlation, yield-related traits, seed-quality traits

Key findings: In rice (O. sativa L.), grain yield sustained direct influences from effective tillers and panicle weight, while significant variability in seed quality traits offers scope for further improvement. Promising genotypes, such as V14 with high protein, V10 (high lipid), and V15 with high amylose content, were successful in their identification as ideal candidates for targeted rice breeding programs.

Soybean (Glycine max L.) production often experiences constraints from drought stress, which significantly reduces yield in tropical areas. The pdh1 gene, known to support pod-shattering resistance, has shown significant potential for enhancing drought tolerance. Therefore, this study aimed to examine the performance of tropical soybean genotypes carrying the pdh1 gene in response to drought stress during flowering to pod formation. A randomized complete block design with factorial arrangement had three replications. The factors included 25 genotypes and two water supply treatments. The water supply treatment consisted of D0=±80% and D1=±50% field capacity (FC), corresponding to soil water potentials of -0.47 and -1.42 MPa, respectively. The yield-related traits’ analysis used 15 drought tolerance indices. The results showed AP21 and AP46 lines with the pdh1 gene were considerably high-yielding and drought-tolerant genotypes. Substantial associations of yield in stress (Ys) and normal condition (Yn) were evident between genotypes with high geometric mean production (GMP), mean production (MP), stress tolerance index (STI), yield index (YI), and low stress susceptibility index (SSI). The results showed genotypes carrying the pdh1 gene can potentially increase drought tolerance in soybeans. The high yield under drought primarily referred to better retention of pod numbers, seed numbers, and seed size.

Keywords: Soybean (G. max L.), water deficit conditions, long juvenile, seed yield, drought tolerance indices, reproductive stages

Key findings: Soybean (G. max L.) genotypes carrying the pdh1 gene showed the highest potential for enhancing drought tolerance in soybeans. Principal component and biplot analyses confirmed that indices, such as high GMP, high MP, STI, and YI, and low SSI, emerged as effective measures for selecting high-performance genotypes under drought stress conditions.

Germanium (Ge) is a metalloid with chemical properties similar to silicon (Si). In Si accumulators like rice (Oryza sativa L.), micromolar concentrations of Ge can result in necrotic lesions and chlorosis. Ge phytotoxicity has been employed to great effect to identify rice mutants defective in silicon (Si) uptake, leading to the cloning of the first Si transporters in plants. A population of M₄ mutants derived from chemical mutagenesis of the temperate japonica Kitaake underwent Ge screening to identify mutants with more rapid development of Ge-induced lesions than the wild type. From 30 mutant lines identified in the preliminary screening, the line designated KDS-557B emerged as hypersensitive, exhibiting a more rapid development of necrotic lesions even at 5 μM GeO₂, a 10-fold lower concentration than the normal used for screening. An analysis of mapping populations from crosses of KDS-557B with Kitaake (χ2 = 2.63, df = 1, P = 0.105, not significant at P ≤ 0.01) and a tropical japonica variety, Sabine (χ2 = 0.04, df = 1, P = 0.841, not significant at P ≤ 0.01) supported a single gene recessive mutation model. Further characterization of KDS-557B will contribute to understanding the interaction of metalloid elements and plants.

Keywords: Rice (O. sativa L.), induced mutations, germanium, toxicity, hypersensitivity

Key findings: Identification of a rice (O. sativa L.) mutant exhibiting hypersensitivity to the phytotoxic metalloid germanium was successful. This mutant, which exhibits a single gene recessive mode of inheritance, and its further characterization will contribute to advancing our understanding of the interaction of crop plants with metalloid elements in the environment.

Increasing rice (Oryza sativa L.) production is essential to meet global food demands amidst population growth, climate change, and limited agricultural resources. However, higher production paired with increased fertilization reduces fertilizer efficiency in rice crops, raises production costs, and negatively impacts the environment. The green super rice (GSR) ideotype’s development was successful in achieving high productivity with low input, tolerance to abiotic stress, and resistance to biotic stress. The technology of anther culture and mutation can be helpful in accelerating the development of new varieties. This study aimed to evaluate agronomic characters and the tolerance of double haploid (DH) lines derived from the Inpari 42 Agritan GSR mutant under low fertilization dosage. The experiment arrangement was in a split-plot design, with fertilizer dosage as the main plot (1/3 dosage, 2/3 dosage, and recommended dosage) and genotypes as the subplot (16 DH lines and two check varieties, which are Inpari 42 and Inpari 45). The recommended dosage of fertilizer had the highest productivity; however, it was not significantly different from the 2/3 dosage of fertilizer. Based on MGIDI selection, the DH lines MS36, MS42, MS45, MS46, and MS51 emerged as promising lines with better yield components and productivity and tolerance index values under the 2/3 fertilizer dosage.

Keywords: Green super rice (O. sativa L.), anther culture, fertilizer efficiency, MGIDI, tolerance indices, grain yield

Key findings: Reducing fertilization in rice (O. sativa L.) cultivation is a feasible strategy to lower production costs and minimize environmental impact. Based on MGIDI selection, five double haploid lines were selected due to better productivity, yield components, and tolerance index values than the parent under a 2/3 fertilizer dosage.

This study investigated the distribution, molecular identification, and genetic analysis of Potato leafroll virus (PLRV) in the Yukari-Chirchik District of Tashkent Region, Uzbekistan, during 2022–2024. Field surveys revealed characteristic PLRV symptoms, including leaf chlorosis, upward rolling, and interveinal yellowing in potato cultivars Arizona, Zarzara, Gala, and Santa. Reverse transcription polymerase chain reaction (RT-PCR) successfully amplified a 726 bp fragment of the coat protein (CP) gene. A novel isolate designated ‘Potato leafroll M-1’ attained successful identification and depositing in the NCBI GenBank (accession number PP981686). Phylogenetic analysis demonstrated 99.58% genetic similarity with the African isolate JEO11-34 and close relationships with German and Canadian strains. Several detected single nucleotide polymorphisms in the CP gene promoter region indicated evolutionary divergence. Reservoir host analysis using real-time PCR identified PLRV in Datura stramonium, Solanum nigrum, Solanum lycopersicum, Physalis floridana, and Dolichos lablab, confirming these species as potential virus reservoirs. This research provides the first molecular evidence of PLRV occurrence in Uzbekistan and validates RT-PCR as an efficient diagnostic tool for early virus detection. The findings establish a scientific foundation for developing virus-resistant potato cultivars and managing reservoir hosts to reduce viral spread.

Keywords: Potato (S. tuberosum L.), potato leafroll virus (PLRV), isolate, RT-PCR, coat protein (CP) gene, Potato leafroll M-1, primer design, phylogenetic analysis

Key findings: The spread of potato (S. tuberosum L.) leafroll virus (PLRV) required monitoring. Through molecular genetic analysis, a new isolate designated as ‘Potato leafroll M-1’ succeeded in being deposited in the NCBI GenBank with the accession number PP981686.

The genus Uncaria (Rubiaceae) is a group of widespread woody plants with optimum diversity. Indonesia has over 103 cultivars of gambir and its wild relatives; however, research on wild Uncaria, particularly in West Sumatra, Indonesia, remains limited. The related study aimed to analyze the phylogenetic relationship of Uncaria spp. in West Sumatra, Indonesia, and recognize the speciation processes in U. gambir as an important germplasm. In this study, the collection of 16 gambir samples came from Pesisir Selatan (Siguntur and Taratak Tempatih) and Lima Puluh Kota (Simpang Kapuak and Ampalu), with 12 samples sequenced using data from the GenBank. Extracting DNA used the CTAB method, amplified with ITS markers, and sequenced. Carrying out the analysis engaged the Bioedit application for alignment and MEGA for phylogenetic reconstruction and genetic distance. The ITS sequence was 623 bp long with a GC content of 61.5%. U. gambir forms a monophyletic clade, found closely associated with the species U. yunnanensis and U. lanosa. The genetic distance (0.099–0.102) between U. gambir and other species was greater than between its own species (0.000–0.003). These results will support the domestication and selection of U. gambir for sustainable breeding and future conservation.

Keywords: Uncaria spp., wild relatives, cultivated species, domestication, ITS, phylogenetic analysis, genetic distance, germplasm conservation, West Sumatra

Key findings: Uncaria gambir constitutes a remarkably homogeneous genetic group characterized by the least intraspecific variation. Its close relationship with the species U. yunnanensis and U. lanosa revealed an evolutionary connection and possible ancestral origin in East Asia. The results support sustainable breeding efforts and future conservation of Uncaria germplasm.

A considerable demand for domestically produced vegetable oil prevails, which can be met by expanding cultivation areas and increasing the productivity of oilseed crops in Uzbekistan. The country’s demand for vegetable oil is about 450,000–500,000, with only 40% covered locally and the rest imported from Russia, Ukraine, and Kazakhstan. The drive for breeding work on safflower (Carthamus tinctorius L.) and flax (Linum usitatissimum L.) crops results from rapidly growing global demand for vegetable oil. Safflower is one of the most promising oil crops, with a high-yield potential and adaptability to extreme environmental conditions under the rainfed farming system. Flax is also a valuable oilseed and technical crop, and its seeds contain up to 50% of high-quality oil. The subsequent research comprised breeding efforts and morphophysiological assessments of safflower and flax under rainfed conditions in Uzbekistan. The key research includes genotype evaluation based on ecological and geographical origins and varietal forms by agro-biological traits, parental genotype selection for hybridization considering ecological and geographical distances, and adaptation to regional cultivation requirements. As a result of the research, the selection of new high-yielding, oil-rich, and stress-resistant genotypes of the safflower and flax was successful.

Keywords: Safflower (C. tinctorius L.), flax (L. usitatissimum L.), breeding efforts, rainfed conditions, biomass, seed yield, 1000-seed weight, seed oil content, water content

Key findings: Safflower cultivars Moydor, 2018/10, and Jizzakh-1 showed the highest yield and resilience under drought conditions. Specifically, Jizzakh-1 had a seed oil content of 30.4% and a 1000-seed weight of 42.3 g. Among flax genotypes, 2021/3 provided the maximum oil content at 39.3%, while the variety Lalmikor had a 1000-seed weight of 5.9 g and biomass accumulation of 168.60 g. These varieties reached high recommendations for breeding programs to improve crop production in rainfed areas.