Seed Yield Loss Research Articles

Survey and molecular characterization of begomovirus, and assessment of yield losses caused by leaf curl disease of sunflower (Helianthus annuus)

A comprehensive survey was conducted during winter (rabi) and rainy (kharif) seasons of 2019–20 to 2021–22 in the Kurnool, Nandyal, and Prakasam districts of Andhra Pradesh, focusing on the incidence of leaf curl disease in hybrid sunflower (Helianthus annuus L.) crop. The results revealed a high incidence of the disease, ranging from 40–94.5% across most of the surveyed hybrid varieties. Leaf curl-infected samples collected from the surveyed fields were analyzed by PCR using specific primers for the DNA-A component of the virus to confirm the presence of the pathogen. The PCR-amplified fragments were cloned and sequenced. Sequence analysis revealed that the sunflower isolate (Snf-AP) shared 99.2% nucleotide identity with the tomato leaf curl Karnataka virus (ToLCKV), which infects sunflower crops in Karnataka. This indicates a strong geographical and genetic connection between the viral strains affecting sunflowers in Andhra Pradesh and Karnataka. This genetic similarity is significant, as it suggests that the same or closely related viral strains are responsible for sunflower leaf curl disease across broader regions. The disease was found to affect sunflowers at all growth stages, with the highest incidence (42.3%) observed at the star bud stage. Infection at the star bud stage leads to substantial seed yield losses, with reductions of up to 82.8%. This level of damage underscores the economic impact of early infections, as yield losses of this magnitude can severely affect the profitability of sunflower farming. Additionally, a positive correlation was found between the whitefly population, weather parameters, and disease development.

Optimized irrigation and fertilization can mitigate negative CO2 impacts on seed yield and vigor of hybrid maize

Seed yield and vigor of hybrid maize determine the planting, yield, and quality of maize, and consequently affect food, nutrition, and livelihood security; however, the response of seed yield and vigor to climate change is still unclear. We established an optimization-simulation framework consisting of a water‑nitrogen crop production function, a seed vigor and a gridded process-based model to optimize irrigation and nitrogen fertilization management, and used it to evaluate seed yield and vigor in major seed production locations of China, the USA, and Mexico. This framework could reflect the influence of water and nitrogen inputs at different stages on seed yield and vigor considering the spatio-temporal variability of climate and soil properties. Projected seed yield and vigor decreased by 5.8–9.0 % without adaptation by the 2050s, due to the 1.3–5.8 % decrease in seed number and seed protein concentration. Seed yield was positively correlated with CO2 and negatively correlated with temperature, while seed vigor depended on the response of components of seed vigor to climatic factors. Under optimized management, the direct positive effects of temperature on seed protein concentration and CO2 on seed number were strengthened, and the direct negative effects of temperature on seed number and CO2 on seed protein concentration were weakened, which mitigated the reductions in both seed yield and vigor. Elevated CO2 was projected to exacerbate the 2.6 % seed vigor reduction and mitigate the 2.9 % seed yield loss without adaptation, while optimized management could increase seed yield by 4.1 % and mitigate the 2.2 % seed vigor reduction in the Hexi Corridor of China, and decrease the seed yield and vigor reduction by 2.4–5.8 % in the USA and Mexico. Optimized management can strengthen the positive and mitigate the negative effects of climate change on irrigated hybrid maize and inform high-yield and high-quality seed production globally.

Effect of integration of eco-friendly components for the management of stem rot of berseem caused by Sclerotinia spp under in vivo conditions

Stem rot of berseem caused by Sclerotinia spp. is the most devastating and cosmopolitan plant disease, infecting more than 400 species of plants worldwide. The disease is reported to cause by a soil-borne plant pathogen and is responsible for significant amount of green fodder and seed yield losses in the forage crop. Integrated disease management is the practice of using a range of measures to prevent and manage diseases in crops. Total seven different combinations of eco-friendly components were integrated for their effect on the management of stem rot of berseem caused by Sclerotinia spp. under in vivo conditions. The experiment was conducted in a polyhouse using sick soil pots. Out of them, treatment T7 (TRN-10 + Eupatorium adenophorum + panchgavya + ghanjeevamrit) was found the most promising integration for the management of the stem rot disease, with terminal disease severity (13.17%) & AUDPC value (177.33) and maximum disease control (75.00%) after 35 days of inoculation. Thus it was inferred that the integration of various eco-friendly management components proved to be most effective in reducing the disease severity of stem rot of berseem.. KEYWORDS :Berseem, fodder, stem rot, Sclerotinia spp. , yield loss

How do drought and heat affect the response of soybean seed yield to elevated O3? An analysis of 15 seasons of free-air O3 concentration enrichment studies.

The coincidence of rising ozone concentrations ([O3]), increasing global temperatures, and drought episodes is expected to become more intense and frequent in the future. A better understanding of the responses of crop yield to elevated [O3] under different levels of drought and high temperature stress is, therefore, critical for projecting future food production potential. Using a 15-year open-air field experiment in central Illinois, we assessed the impacts of elevated [O3] coupled with variation in growing season temperature and water availability on soybean seed yield. Thirteen soybean cultivars were exposed to a wide range of season-long elevated [O3] in the field using free-air O3 concentration enrichment. Elevated [O3] treatments reduced soybean seed yield from as little as 5.3% in 2005 to 35.2% in 2010. Although cultivars differed in yield response to elevated [O3] (R), ranging from 17.5% to -76.4%, there was a significant negative correlation between R and O3 dosage. Soybean cultivars showed greater seed yield losses to elevated [O3] when grown at drier or hotter conditions compared to wetter or cooler years, because the hotter and drier conditions were associated with greater O3 treatment. However, year-to-year variation in weather conditions did not influence the sensitivity of soybean seed yield to a given increase in [O3]. Collectively, this study quantitatively demonstrates that, although drought conditions or warmer temperatures led to greater O3 treatment concentrations and O3-induced seed yield reduction, drought and temperature stress did not alter soybean's sensitivity to O3. Our results have important implications for modeling the effects of rising O3 pollution on crops and suggest that altering irrigation practices to mitigate O3 stress may not be effective in reducing crop sensitivity to O3.

Relationship of seeding rate to biological nitrogen fixation and seed production of red clover in Saskatchewan

In Saskatchewan, red clover is often grown for seed production. However, there is no recognized or data supported seeding rate for seed production of red clover in Saskatchwan. The objectives of this study were to identify an optimal seeding rate for seed production and biological nitrogen fixation (BNF) and to examine their relationships under semi-arid conditions. This experiment was conducted under field conditions using six different seeding rates (0.5, 2.5, 4.5, 6.5, 8.5 and 10.5 kg ha-1) at Melfort and Clavet, SK in 2018 and 2019, and seed yield, biomass, plant density, and BNF were measured. In our study, red clover was able to compensate for the range of seeding rates between 2.5 and 10.5 kg ha-1 without seed yield loss and BNF reduction, whereas biomass production and BNF were higher at 4.5 kg ha-1 seeding rate than in 0.5 kg ha-1 at Melfort, but no seeding rate effects were found at Clavet. Regardless of location, biomass was always positively correlated with BNF. However, no association was found between seed yield and BNF. Our results suggest that 4.5 kg ha-1 is ideal for seed production, BNF and biomass production of red clover in Saskatchewan.

The effects of high temperature and low humidity on crop water stress index of seed pumpkin plants (Cucurbita pepo L.) in semi-arid climate conditions

This study aimed to evaluate the effects of high temperature and low humidity on the crop water stress index (CWSI) of seed pumpkin plants grown under semi-arid climate conditions to determine the optimum irrigation time. This research unveils the critical impact of high temperature and low humidity on seed pumpkin growth, emphasizing the vital role of the CWSI in optimizing irrigation strategies and seed yield. Moreover, the relationship between CWSI, physiological parameters, and seed yield of the pumpkin was investigated. The mean CWSI values in the I70 (0.40) and I35 (0.56) treatments were 42% and 100% higher, respectively than those in the full irrigation (I100) treatment (0.28). While the I70 treatment showed manageable water stress with minimal impact, the I35 treatment experienced severe stress, significantly reducing crop growth and yield. The mean seed yield (SY) in the I70 treatment increased to 1245.2 kg ha–1 compared to I35 (903.3 kg ha–1) but remained lower than I100 (1339.3 kg ha–1). The CWSI had negative correlations (p ≤ 0.01) with seed yield, chlorophyll content, and leaf area index, while it had positive correlations with water use efficiency and irrigation water use efficiency (p ≤ 0.01). This study showed that pumpkins could be grown successfully at 30% water deficit conditions, and a water deficit higher than 30% may cause a significant seed yield loss in semi-arid climate conditions. In addition, the results highlight the importance of optimal irrigation and CWSI monitoring for informed irrigation decisions and sustainable agricultural practices. Therefore, moderate water deficit (I70) can be adopted in pumpkin cultivation as an alternative to full irrigation.

Biology and management of Coleophora deauratella (Lepidoptera: Coleophoridae) in red clover seed-growing regions in North America and New Zealand

Abstract Red clover (Trifolium pratense L.), a perennial forage legume belonging to the Fabaceae family, is grown for seed in many temperate regions of the world. Coleophora deauratella Leinig and Zeller (Lepidoptera: Coleophoridae) is a significant insect pest occurring globally in several primary red clover seed-producing regions. Coleophora deauratella inflicts crop damage by larval feeding on developing seed within individual florets, thus reducing seed yield. The first detection of C. deauratella and seed yield losses up to 90% were reported in the Peace River region of Alberta, in western Canada, in 2006, signifying its damage and potential threat to other red clover seed-producing areas of the world as an invasive insect pest species. As a result, crop stand age was reduced to 1 yr to mitigate seed yield loss caused by this pest in second-year fields in Alberta. Coleophora deauratella was first discovered in western Oregon in 2011, but the resulting economic damage remains unknown after more than a decade of its discovery. The first confirmed case of C. deauratella and tremendous seed yield devastation in red clover seed crops in the mid-Cantebury region of New Zealand occurred in 2016. Continued monitoring efforts in Oregon and New Zealand revealed that pest populations started receding after 2018, and the presence of unknown biocontrol agents, climatic, or genetic factors was speculated for its lower establishment rate. In this article, we discuss C. deauratella biology, ecology, and pest status in North America and New Zealand, along with the key research highlights to control C. deauratella.

Screening of Soybean Advanced Breeding Lines for Resistance Against the Southern Green Stink Bug Nezara viridula L (Hemiptera: Pentatomidae) under Free-Choice and No-Choice Tests

Background: The southern green stink bug (SGSB), Nezara viridula, is a potentially harmful pod sucker insect found in soybean. Objective: The objective of this study was to evaluate the resistance level of several soybean advanced breeding lines against the southern green stink bug N. viridula under the free-choice and no-choice tests. Methods: The research materials were 14 advanced breeding lines and four check cultivars. The experiment was conducted in Malang, East Java, Indonesia, during the dry season I and II 2022. The resistance evaluation of the soybean genotypes against the N. viridula was under the Free-Choice test (FC) and the No-Choice test (NC). The newly emerged adults N. viridula were infested when plants reached the R5 stage. The data were observed for damage intensity, yield and yield components. Results: The intensity of pod damage in the FC ranged from 20.09 to 46.40%, meanwhile, in the NC was 25.63 to 67.63%. This shows that the NC condition provides more selection pressure than the FC. Each genotype exhibited different resistance reactions in the FC and NC. The pod damage intensity had a significant negative correlation with seed yield both in the FC and NC. Conclusion: The No-Choice test (NC) provided a higher selection pressure for resistance to SGSB than the Free-Choice test (NC). The use of SGSB-resistant cultivars will prevent soybean seed yield losses. A new finding in this study, two soybean genotypes Anj/Rjbs-305 and Anj/Rjbs-306 were resistant to SGSB. Both genotypes exhibit good agronomic performance (high yield and large seed size), thus can be proposed as new soybean varieties to be developed in the country.

Turnip yellows virus variants differ in host range, transmissibility, and virulence.

Turnip yellows virus (TuYV; family Solemoviridae, genus Polerovirus, species Turnip yellows virus) is a genetically diverse virus that infects a broad range of plant species across the world. Due to its global economic significance, most attention has been given to the impact of TuYV on canola (syn. oilseed rape; Brassica napus). In Australia, a major canola-exporting country, TuYV isolates are highly diverse, with the most variation concentrated in open reading frame 5 (ORF 5), which encodes the readthrough domain (P5) component of the readthrough protein (P3P5), which plays an important role in host adaptation and aphid transmission. When analysing ORF 5, Australian TuYV isolates form three phylogenetic groups with just 45 to 49% amino acid sequence identity: variants P5-I, P5-II, and P5-III. Despite the possible implications for TuYV epidemiology and management, research examining phenotypic differences between TuYV variants is scarce. This study was designed to test the hypothesis that three TuYV isolates, representing each of the Australian P5 variants, differ phenotypically. In particular, the host range, vector species, transmissibility, and virulence of isolates 5414 (P5-I5414), 5509 (P5-II5509), and 5594 (P5-III5594) were examined in a series of glasshouse experiments. Only P5-I5414 readily infected faba bean (Vicia faba), only P5-II5509 infected chickpea (Cicer arietinum), and only P5-I5414 and P5-III5594 infected lettuce (Lactuca sativa). Myzus persicae transmitted each isolate, but Brevicoryne brassicae and Lipaphis pseudobrassicae did not. When using individual M. persicae to inoculate canola seedlings, P5-I5414 had significantly higher transmission rates (82%) than P5-II5509 (62%) and P5-III5594 (59%). As indicated by enzyme-linked immunosorbent assay absorbance values, P5-I5414 reached higher virus titers in canola than P5-II5509, which, in turn, reached higher titers than P5-III5594. P5-I5414 was also more virulent in canola than P5-II5509 and P5-III5594, inducing more severe foliar symptoms, stunting, and, in one of two experiments, seed yield loss. Results from this study compared to those of previous studies suggest that analysis of ORF 5 alone is insufficient to assign isolates to coherent strain categories, and further sequencing and phenotyping of field isolates is required.

Evaluation of Introgressed Lines of Sunflower (Helianthus annuus L.) under Contrasting Water Treatments

Drought stress is a major production constraint in crops globally. Crop wild relatives are important sources of resistance and tolerance for both biotic and abiotic stresses, respectively. A breeding program was initiated to introgress drought tolerance in sunflowers through hybridization between the wild species Helianthus argophyllus and the cultivated pool of H. annuus. Selection was carried out from the F2 to F5 segregating populations for the silver canopy, high cuticular wax, small leaf area, single heading and high oil content. Cuticular wax ranged between 8.72 µg g−1 and 17.19 µg g−1 in the F5 offspring. The selected F5 breeding lines were self-pollinated to obtain the F6 generation. Thereafter, this F6 was compared with the non-adapted elite sunflower germplasm in a factorial complete randomized design with different water treatments; i.e., comparing fully irrigated (100%, T0) versus 75% (T1), 50% (T2) and 25% (T3) of total irrigation. The comparison between the two types of the germplasm showed that drought-tolerant breeding lines had a comparatively lesser decrease in leaf area (0, 11, 22%) and shoot length (4, 21, 28%) than the elite germplasm, which experienced a decrease in leaf area (21%, 33% and 40%) and shoot length (17, 27 and 34%) under the various drought treatments. Moreover, drought-tolerant breeding lines had 100% more root shoot ratios than the elite germplasm (20%) in T3 when compared with control. Several drought-tolerant promising lines (D-2, D-5 and D-27) were selected due to their high leaf area, great root length and increased root to shoot ratio under T3. Some of the lines could be directly used for the development of drought-tolerant hybrids. Combining ability testing indicated that D-27 (F7) was a good general combiner for seed yield plant−1 and oil content after mating with male-line RSIN.82. Resulting hybrids could help to minimize seed yield loss due to water stress and to achieve profitable cultivation of sunflowers in arid regions of Pakistan.

Влияние физиологически активных веществ на семенную продуктивность эфиромасличных лекарственных культур

Supplying of the pharmaceutical industry with medicinal raw materials is carried out mainly due to it cultivation on an industrial scale. For three years (2020–2022), in the conditions of the Krasnodar region in the fields of the North Caucasian branch of VILAR there were studied the ways of hormonal regulation of the formation of seed productivity of essential oil crops – two varieties of Matricaria chamomilla and Salvia officinalis. The results of the conducted research showed that the treatment of plants in the budding phase with growth regulators Zircon (0.04 l/ha) and Gibbersib (0.03 kg/ha) led to a more friend-ly flowering of plants and, accordingly, to an increase in the yield of Matricaria seeds by 15–28 % and Sal-via by 20–28 %. At the same time, their quality im-proves – the weight of 1000 seeds increase by 6–14 %. The use of these growth regulators contributes to increasing the resistance of the studied medicinal crops to dry weather conditions and ensures a reduction in seed yield losses up to 12–26 %, while in the control it was till 22–33 %. With the complex application of Lignohumat (0.05 l/ha) in the initial growth phases of the abovementioned crops and growth regulators (Zircon and Gibbersib) in the budding phase, an increase in seed yield is observed, both in comparison with the control and with some regulators. The highest efficiency was noted in the Lignohumat + Zircon variant, where the seed yield exceeded the control by 28–39 % and in the variant with Zircon – by 9–13 %.

Evaluation of methods to assess the quality of cryopreserved Solanaceae pollen

Solanaceae pollen cryopreservation is a common practice in the hybrid seed production industry worldwide, enabling effective hybridization across geographical and seasonal limitations. As pollination with low quality pollen can result in significant seed yield loss, monitoring the pollen quality has become an important risk management tool. In this study, pollen quality analysis methods were evaluated for their suitability for routine quality control of cryopreserved pollen batches. The assessments, including pollen viability, pollen germinability and pollen vigor analysis, were conducted in two locations on a diverse set of cryopreserved tomato and pepper pollen batches. While the viability obtained by Impedance Flow Cytometry (IFC) can be interpreted as the pollen’s potential to germinate, the in vitro germination assay directly quantifies this functionality under given assay conditions. A linear correlation was found between pollen viability obtained by IFC and in vitro germinability. In conclusion, IFC is the most suitable tool for applications and industries requiring a high degree of automation, throughput, repeatability, and reproducibility. In vitro germination assays are suitable for studies within certain temporal and geographic limitations, due to difficulties in standardization. On the other hand, vigor assessments are not sufficiently addressing the needs of the industry due to poor reproducibility and low throughput.

Modified screening method of middle american dry bean genotypes reveals new genomic regions on Pv10 associated with anthracnose resistance.

Anthracnose, caused by the fungal pathogen Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib., is one of the most devastating diseases in dry bean (Phaseolus vulgaris L.) with seed yield losses up to 100%. Most anthracnose resistance genes thus far identified behave in a dominant manner and were identified by seedling screening. The Middle American Diversity Panel (MDP; n=266) was screened with a modified greenhouse screening method to evaluate the response to anthracnose race 73. Thirty MDP genotypes exhibited resistance to the race of which 16 genotypes were not known to contain anthracnose resistance genes to race 73. GWAS with ~93,000 SNP markers identified four genomic regions, two each on Pv01 and Pv10, associated race 73 resistance. A likelihood-ratio-based R2 analysis indicated the peak four SNP markers are responsible for 26% of the observed phenotypic variation, where one SNP, S10_072250, explains 23% of the total variation. SNP S10_072250 is associated with a new region of anthracnose resistance and is in an intron of a ZPR1-like gene. Further greenhouse testing of the 16 resistant lines without previously known resistance to race 73 revealed various levels of resistance under various levels of disease pressure. Disease resistance was further characterized in the field using four representative genotypes. GTS-900 and Remington exhibited field resistance while Merlot and Maverick were susceptible. Field testing with two different fungicide regimes revealed the resistant genotypes had no significant disease differences. The results suggest resistance to anthracnose may differ at various growth stages and that breeders have been selecting for major genes at early seedling stages while ignoring the effect of alternative genes that may be active at later stages. The newly identified resistant lines may be related to Age Related Resistance (ARR) and could be exploited as parental sources of anthracnose resistance in addition to already known major genes. The physical localization of the multiple regions of resistance confirms the presence of two clusters of disease resistance genes on Pv01 and identifies two new regions of anthracnose resistance on Pv10 possibly associated with ARR. Future research should look at the mode of inheritance of this resistance and its effect when combined with other anthracnose resistance loci.

First report of Alternaria alternata causing leaf spot on Nelumbo nucifera plants in China.

White lotus (Nelumbo nucifera) is an aquatic plant of the Nymphaeaceae family that primarily serves as an ornamental plant and is an important cash crop in China. In May 2020, an unknown leaf disease affecting these plants was first detected in White Lotus Science and Technology Expo Park in Guangchang County, Fuzhou City, Jiangxi Province (26.79° N, 116.31° E). The disease caused approximately 30-40% of leaves to die, and led to 15 to 20% in seed yield losses. This disease was characterized by the formation of irregular yellow-brown to dark-brown spots during the initial phases of infection. As the disease is developing, these spots expanded until they were generally round and brown to purple-brown in color, with a yellow halo surrounding the expanding spots. In an effort to characterize the causative pathogen, a small ~5×5 mm leaf tissue section from the boundary between normal and diseased tissue was collected, and sterilized with the following regimes: 30 s with 75% ethanol, soaked in 0.1% mercuric chloride for 30 s, washed thrice with sterile water, and transferred onto potato dextrose agar (PDA) plate, and placed in an illumination incubator (12 h light/dark) at 28 °C± 1°C for 5 days. Seven pure cultures were obtained from ten diseased leaves. For pathogenicity testing, a hyphal inoculation strategy was employed, with all studies being conducted at the Plant Pathology Laboratory of Jiangxi Agricultural University. Five mm discs were selected from three separate cultures and one control (PDA). Healthy leaves of lotus seeds were treated with 4 treatments per leaf including three separate cultures and one control that were treated with the test pathogen. The experiments were repeated three times with three biological replicates. Healthy leaves were covered with moisturized sterile cotton balls and fixed to the leaf surface with transparent tape. The inoculated lotus seedlings were kept in greenhouse incubator at 28 °C± 3°C and relative humidity of 70 to 80%. Following a 14-day incubation period, brown spots began to manifest at all sites inoculated with the test pathogen whereas the control spots remained healthy. Diseased spots were then separated. The same pathogen was once again successfully isolated and identified microscopically, thus fulfilling Koch's postulates. Six isolates were characterized. Ovoid or elliptical conidia were brown to light-brown in color with a short beak, 1-5 diaphragms, and 0-3 mediastinum. The diameter of these conidia were thick (13.8-44.0×7.5-16.3 µm; average: 24.0×11.9 µm, n=50). These morphological characteristics were consistent with Alternaria alternata. The ITS4/ITS5, EF1-728F/EF1-986R, AltF/AltR, OPA10-2R/OPA10-2L, EPGF/EPGR and KOG1058F2/KOG1058R2 primer sets were then used to conduct molecular identification by amplifying key transcription elongation factor and internal transcriptional spacer regions, yielding sequences that were 99%-100% similar to Alternaria alternata (GenBank No: MK396606, MT178329, MN184998, MN894688, MT849815 and KP125234). Sequences were deposited in GenBank with accession numbers MW898580 (ITS, 620 bp), MW981281 (EF1-α, 284 bp), MZ514094 (Alt a1, 477 bp), MZ514095 (OPA10-2, 716 bp), MZ514096 (endoPG, 465 bp) and MZ514097 (KOG1058, 877 bp). Nelumbo nucifera is an important aquatic cash crop in China, and this is the first study we are aware of demonstrating the presence of a leaf disease caused by Alternaria alternata in Nelumbo nucifera plants anywhere in the world. These findings may offer a foundation for efforts to prevent diseases caused by Alternaria alternata.

Estimation of avoidable yield losses in Indian mustard (Brassica juncea L.) due to mustard aphid, Lipaphis erysimi (Kaltenbach) in Rewari district, Haryana, India

The Indian mustard (Brassica juncea L.) is a significant oilseed crop in India. The sap-sucking pest, mustard aphid (Lipaphis erysimi) emerged as a major threat to this crop, which can harshly reduce yield. The research experiment was carried out during the Rabi seasons, 2019-20 and 2020-21 at Rewari, Haryana to comprehend the influence of L. erysimi infestation on different yield parameters of B. juncea in the field. The two cultivars of B. juncea namely, RH 725 and RB 50 were raised in a paired plot design with two different sets viz., protected and unprotected and thirteen replications each set were kept. The protected set was sprayed with insecticide Dimethoate 30 EC @ 625 ml ha-1 one time only, whereas unprotected set was kept free from insecticidal application for natural infestation of the pest. The present investigation revealed that under unprotected conditions, the yield parameters viz., weight of 100 siliquae, 100 siliquae husk, 10 main apical shoots (10 cm) and 1000 seeds, as well as seed yield, were significantly (P<0.01) affected by the L. erysimi infestation, while parameter, seed germination percentage influenced non-significantly (P>0.01). The maximum seed yield losses were registered in genotype RH 725 (26.25 %) when compared with RB 50 (25.92 %). All other yield parameters exhibited the same pattern except for three parameters i.e. weight of 100 siliquae, 100 siliquae husk and 10 main apical shoots (10 cm). In conclusion, this research highlights the colossal yield losses inflicted by L. erysimi infestation in B. juncea in unprotected conditions and the utility of insecticidal application in the enhancement of crop yield by management of this insect pest in protected conditions.

The Effects of Foliar Zinc Application on Yield and Quality Components of Pea (Pisum sativum L.) in Mediterranean Climate Conditions

Peas are widely grown, especially in the western region of Turkey with a temperate climate. Pea cultivation areas are decreasing in this region, where the Mediterranean climate is dominant. Zinc deficiency causes seed yield losses in pea cultivation. This study aimed to determine the optimum foliar zinc application to improve the seed yield of the widely planted pea varieties (Karina and Utrillo). For this reason, foliar application of zinc (0-30-60 kg ha-1) was carried out at the beginning of the flowering period. The study was conducted in two growing seasons (2019 and 2020) at Aydin Adnan Menderes University. In this study, plant height, plant stem diameter, the number of seeds per pod, pod length, 100-seed weight, seed yield, seed protein content, protein yield, seed ash content, seed fibre content, seed oil content, and seed zinc content were determined. According to the results obtained, the highest values for pods per plant, 100-grain weight, seed yield, protein ratio, protein yield, and seed zinc content were obtained from 60 kg of zinc ha-1 in both years. However, zinc foliar application did not affect the plant height or plant stem diameter in either year. Although similar values were obtained regarding the characters examined among the cultivars, Karina stood out in seed yield and protein ratio, and Utrillo performed better in seed zinc content. Based on the values we got, we can recommend applying a dose of 60 kg of zinc per hectare per year from the leaf.

GENETIC AND PHYSIOLOGICAL ASPECTS OF SILIQUE SHATTERING IN RAPESEED AND MUSTARD

Rapeseed (Brassica napus L.) and mustard (Brassica juncea L.) are two important oilseed crops grown worldwide for edible oil and meal production, as well as, a source of renewable energy. Silique shattering at the maturity stage is the major cause of seed yield reduction in brassica. Losses in seed yield are more in developing countries due to poor management and the non-availability of combine harvesters. Silique shattering resistance is essential for achieving good seed yield especially in Brassica napus. The silique on plants of rapeseed and mustard mature in different phases due to indeterminate growth habit, which is also a reason for shattering losses. Silique shattering is linked with the creation of a dehiscence zone in a brassica pod. When the siliqua wall loses its hydration, along the length of the siliqua, a few cell layers separate the replum from the pericarp tip of the two silique valves. In the dehiscence zone, it involves the collapse of cell walls and cell separation, as well as, the destruction of the middle lamella and enhanced hydrolytic enzyme activity. To avoid seed yield losses, resistance against silique shattering is essential in rapeseed and mustard cultivars. There are multiple QTLs discovered that control variance in silique shattering. Previous studies validated the shattering process in the model plant Arabidopsis thaliana was controlled by eight different genes. However, their role in controlling silique shattering in rapeseed and mustard is unknown. Modern tools of mutation breeding and genetic engineering, especially CRISPR/Cas9 technology, can be utilized to identify the genetic source for shattering resistance in rapeseed and mustard, which will be helpful for the development of silique-shattering

Physiological Response of Common Bean (Phaseolus vulgaris L.) to Varying Temperature and Irrigation Regimes

Background: Elevated temperature and water stress are the key limiting factors affecting the kidney bean yield. Climate change is projected to enhance these risks for successful crop production. However quantified information, which is limited, on temperatures stress at various growth phases in combination with water regimes, becomes important for optimizing management decisions for higher productivity of kidney bean. The current study is aimed to fill this gap. Methods: A field experiment was conducted during January-April 2020, to investigate the effect of irrigation and temperature regimes on growth parameters and yield of kidney bean. Temperature treatments imposed were elevated temperature for entire crop period i) ~4.6°C ii) ~3.1°C iii) ~2.8°C above mean ambient (19.6°C), iv) ambient temperature Tmax and Tmin regime of 25.9/13.4°C (mean 19.6°C), v) elevated temperature during pre-flowering phase (~3.7°C above mean ambient during that period, 19.6°C), vi) flowering phase (~5.3°C above mean ambient during that period, 23.1°C) and pod-filling phase (~5.2°C above mean ambient during that period, 28.9°C). These were combined with i) two irrigations (applied at sowing and seedling phase) and ii) three irrigations (additional irrigation at pod-filling phase). Result: Elevated temperature regimes led to shortening of the crop duration. LAI, NDVI, net photosynthesis and seed yield were higher in plants exposed to continuous elevated temperature. Heat shock during pre-flowering and flowering led to reduction in yield. Despite exposure to elevated temperature, supplemental irrigation led to higher yield. Seed yield loss was greater when temperature stress coincided with water stress. The negative effects of high temperature were significantly curtailed by provision of supplemental irrigation.

Impact of Imidazolinones on Weeds in Pigeon Pea (Cajanus cajan L.)

Background: Among various biotic factors limiting pigeon pea yield, weeds are of prime importance which can causes seed yield losses up to 80 per cent. Therefore current study aims to evaluate the impact of imidazolinones on weeds in pigeon pea (Cajanus cajan L.). Methods: The experiment was laid out in randomized block design using eighteen treatments replicated thrice. To control the weeds in pigeon pea, imidazolinones alone and its combination with pendimethalin were applied and rest other cultural practices for cultivation of pigeon pea were adopted according to the package and practices of CCA HAU, Hisar. Result: Among all weed controls treatments, two hoeing at 40 and 70 DAS found most effective to control all kind of weeds. PRE application of imidazolinones was comparatively more effective than POE application. Among different weed species, Cynodon dactylon was not controlled by any of the herbicide treatment and PRE application of pendimethalin @ 1000 g/ha did not control Digera arvensis and Cyperus rotundus. Whereas, PRE application of pendimethalin + imazethapyr @ 1000 + 75 g/ha provided best control of total weeds leads to lowest nutrient uptake by weeds. Therefore, PRE application of pendimethalin + imazethapyr @ 1000 + 75 g/ha proved to be an effective and a profitable alternative to the existing recommendation (two hoeing at 25 and 45 DAS) of weed control in pigeon pea in Haryana locality.

Seasonal Incidence of Sesame Webworm, Antigastra catalaunalis (Dup.) and Evaluation of Selected Cultural Control Practices, on Sesame Crop in Erbil City

Background: Sesame Webworm, Antigastra catalaunalis (Dupunchel) is a principal harmful insect of sesame crop. It infests the all shoot parts and stages of sesame plant growth and responsible for approximately seventy percent seed yield loss, therefore, the present study conducted to investigate the seasonal incidence and evaluate two sets of cultural control practices against the damages of the pest larvae. Methods: Field experiment was carried out in the Grda Rasha Research Station-College of Agricultural Engineering Sciences-Erbil-Kurdistan region-Iraq, apart from seasonal incidence, first Set was for assessing the effect of three Sowing Dates viz. 16-May, 15-June, 15-July-2020. The second set was for evaluating the efficiency of three different crop plants viz. corn, cowpea and sunflower plants, intercropped with sesame crop to minimize the capsule infestation damage and seed losses caused by A. catalaunalis (Dup.). The experiments were performed using the RCBD design. Result: The results revealed that the larvae appearance started 2 weeks after sowing and reached its peak 2.31, 2.50 and 2.83 larvae/plant 13 weeks after sowing for all three dates of sowing, the results also showed that the percent capsule infestation and Seed weight loss/25 capsules were 22.27%, 33.85% and 34.16%/25 capsule of sesame plant, for sowing dates mid-May and mid-June and Mid-July respectively. The findings of the intercropping experiment revealed that the least percentages of capsule infestation and losses in seed weight/25 capsules were on sesame plants intercropped with cowpea 18.00% and 21.00% and followed by sesame intercropped with Sunflower and Sesame plants intercropped with corn plants which were 19.40%, 25.60% and 20.20%, 27.60% respectively.