Late Sowing Research Articles

Assessment of Photoperiod Sensitivity and the Effect of Sowing Date on Dry-Season Sorghum Cultivars in Southern Chad

The cultivation of dry-season sorghum on residual moisture in West and Central Africa is highly affected by sowing dates and ecotypes used. Fifty-five dry-season sorghum ecotypes collected from three zones in southern Chadian were sown on two dates, early and late, in 2013 and 2014, in an α-Lattice, and replicated five times to evaluate the effect of sowing date on potential yield, flowering time, and other agro-morphological traits and to determine their photoperiod sensitivity. Trials were conducted in the research fields at the Agricultural Research Extension Farm in Youé, Chad. Year, sowing date, and their interaction significantly affected most of the assessed traits. Delaying sowing significantly decreased potential yield, duration of vegetative phase, and other agro-morphological traits, except staygreen. All cultivars were photoperiodic with late sowing requiring a lower cumulative growing degree unit to flower. The flowering window was not affected by sowing dates across cultivars; however, the flowering time was affected by a decrease in daylength, but not low night temperatures. Generally, late sowing decreased potential yield across cultivars. However, this decrease varied with the region of origin, with seven cultivars having average potential yields at or above the regional potential yield of 1 t/ha, irrespective of year or sowing dates.

NDVI and grain fill duration are important to be considered in breeding for terminal heat stress tolerance in wheat

AbstractTerminal heat stress is a major constraint for taking a profitable crop of wheat by small and marginal farmers in the Indo‐Gangetic Plains of south Asia. Hence, breeders remain in constant search for heat‐tolerant genotypes. This study was done with the purpose to find out high‐yielding wheat genotypes that perform stably under terminal heat stress as well as to conclude an easy phenotyping trait for this objective. A cross (HUW 234 × HUW 468) was made using two popular cultivars of the eastern Gangetic Plains of India. HUW 234 carries terminal heat tolerance whereas, HUW 468 is high yielding but suffers from terminal heat stress when planted late. So obtained 167 recombinant inbred lines (RILs) were exposed to both timely sown (TS) and late sown (LS) conditions at three locations for two consecutive years 2016–17 and 2017–18 at Varanasi (Uttar Pradesh), Jabalpur (Madhya Pradesh) and Pusa, Samastipur (Bihar). Combined ANOVA revealed that normalized difference vegetation index (NDVI) at anthesis stage (NDVI_AH) and grain filling duration (GFD) was significant for genotype (G), environment (E) and genotype × environment interaction (GEI). Likewise, differences were significant for grain yield (GY) and 1000‐grain weight (TGW). AMMI analysis revealed similar results. However, NDVI_AH showed low variation under heat stressed late sown conditions. Furthermore, the which‐won‐where model and mean versus stability identified the best performing, above‐average yielding and stable lines across the environments. Correlation among measured traits revealed that NDVI_AH had a significant association with GY in most of the environments. Several lines that performed superior to better parent for GY also showed higher values for NDVI_AH and GFD. The study demonstrates that NDVI_AH and GFD appear to be important traits to be considered while breeding for terminal heat stress tolerance in wheat.

Evaluation of selection indices for heat tolerance and their correlation with yield in some chickpea (Cicer Arietinum L.) genotypes of sudan

The major a biotic stresses affecting chickpea production are high and low temperature, drought and salinity. Heat stress is a major a biotic stress factor, constraining chickpea production worldwide. This study was conducted to identifying chickpea genotypes combining heat tolerance and high yield potential and to study correlation among the heat tolerance indices. The genotypes were tested under different field-growing conditions, normal sown (non – heat stress) and late sown (heat stress) at two locations, Merowe and Gezira during winter season 2018/2019. The trials were laid out in alpha lattice design with three replications. Eight heat tolerance indices, which were most frequently used in plant breeding including, geometric mean productivity (GMP), yield index (YI), mean productivity (MP), stress susceptibility index (SSI), stress tolerance index (STI), tolerance index (TOL), sensitivity heat index (SHI) and relative heat index (RHI) were calculated based on seed yield under heat stress (Ys) and non – heat stress (Yp) conditions. Under both environments, the results from combined analysis of variance showed that there were highly significant differences among the genotypes for all traits studies. There were highly significant differences observed among the tested chickpea genotypes response to heat stress. Seed yield in stress (Ys) condition was positive and highly significant correlated with geometric mean productivity, yield index, stress tolerance index and relative heat index. The Ys was negative and highly significant correlated with stress susceptibility index and sensitivity heat index. Seed yield in non-stress (Yp) condition was positive and significant correlated with geometric mean productivity, yield index, stress tolerance index and tolerance index. The results of this research showed that the six indices, GMP, YI, SSI, STI, SHI and RHI can be used as optimal indicators for screening heat tolerant chickpea genotypes. Nine genotypes including four released improved varieties (Shiekh Mohamed, Wad Hamid, Salwa and Hwata) and five genotypes (no. 11, 4, 26, 30 and 34) are most stable chickpea genotypes for heat tolerance and can be further used in breeding program. These genotypes can be used in the chickpea national breeding program to develop varieties with improved heat tolerance in Sudan. Genotype no. 11 (FLIP 08-59 C) was release by Sudan national variety release committee for commercial production under the name Elbarkal in September 2022 to will be grown in Gezira, River Nile and Northern States of Sudan.

AMMI and GGE biplot analysis of yield under terminal heat tolerance in wheat.

Wheat is an important cereal crop that helps to meet the food grain needs of people all over the world. Heat stress is one of the most significant abiotic stresses that wheat crops face during terminal growth stages in the wheat growing regions like India. It is very important to identify heat tolerant genotypes to be used as donors for breeding tolerant varieties. Thirty-six wheat genotypes were evaluated under different sowing dates viz., Timely sown (TS), Late sown (LS) and very late sown (VLS), and the fourth was sown in the Temperature controlled phenotyping facility (TCPF) across two years. Genotypes were planted following lattice square design with two replications. Data was recorded for yield and yield contributing traits and analysed using selection indices as well AMMI and GGE biplot stability models. Heat stress affected all the traits under different heat environments which ranged from 1.6% (Spikelet number) to 37.2% (grain yield). Regression analysis indicated that the thousand grains weight (R2 = 0.50) contributed significantly towards grain yield under heat stress. Stress susceptibility index (SSI) found genotypes GW322, RAJ3765, Raj4037and MACS6145 as heat tolerant whereas, Stress Tolerance Index (STI) identified C306, HD2967, WH1080, WH730, DBW90, HD2932, DBW17, RAJ3765 as heat tolerant and high yielding. AMMI biplot analysis indicated stable genotypes DBW90, WH730, RAJ4083, CBW38, HD2932, NI5439, WR544, whereas GGE biplot analysis revealed stable genotypes NIAW34, NI5439, RAJ4083, DBW90, PBW590, Raj3765, HUW 510, WH730, HD2967 and UP2382. Heat stress affects significantly all yield contributing traits. Thousand grain weight was the most important trait that can be used as a selection criterion for selecting tolerant lines. Based on selection indices and both AMMI and GGE analysis, genotype RAJ3765 was identified to be highly heat tolerant with good grain yield.

Effect of delayed sowing on grain number, grain weight, and protein concentration of wheat grains at specific positions within spikes

Delays in sowing have significant effects on the grain yield, yield components, and grain protein concentrations of winter wheat. However, little is known about how delayed sowing affects these characteristics at different positions in the wheat spikes. In this study, the effects of sowing date were investigated in a winter wheat cultivar, Shannong 30, which was sown in 2019 and 2020 on October 8 (normal sowing) and October 22 (late sowing) under field conditions. Delayed sowing increased the partitioning of 13C-assimilates to spikes, particularly to florets at the apical section of a spike and those occupying distal positions on the same spikelet. Consequently, the increase in grain number was the greatest for the apical sections, followed by the basal and central sections. No significant differences were observed between sowing dates in the superior grain number in the basal and central sections, while the number in apical sections was significantly different. The number of inferior grains in each section also increased substantially in response to delayed sowing. The average grain weights in all sections remained unchanged under delayed sowing because there were parallel increases in grain number and 13C-assimilate partitioning to grains at specific positions in the spikes. Increases in grain number m–2 resulted in reduced grain protein concentrations as the limited nitrogen supply was diluted into more grains. Delayed sowing caused the greatest reduction in grain protein concentration in the basal sections, followed by the central and apical sections. No significant differences in the reduction of the grain protein concentration were observed between the inferior and superior grains under delayed sowing. In conclusion, a 2-week delay in sowing improved grain yield through increased grain number per spike, which originated principally from an increased grain number in the apical sections of spikes and in distal positions on the same spikelet. However, grain protein concentrations declined in each section because of the increased grain number and reduced N uptake.

Foliar fungicides help maize farmers reduce yield gaps in late sown crops in a temperate region

Foliar diseases produce significant maize (Zea maize L.) yield reductions, increasing yield gaps and threatening food security. In the central temperate region of Argentina 50 % of maize cropped is grown under late sowing dates (December), where meteorological conditions are favorable to disease development, such as higher temperatures during initial stages and higher relative humidity. However, no major testing was reported to fully understand yield responses to foliar fungicides. Our objectives were to quantify the impact of foliar fungicide application on grain yield in late sown crops, and to identify genotype, management, and environmental interactions modulating the yield response. We conducted 21 on-farm trials during 6 growing seasons (2014/15 and from 2016/17 to 2020/21) with and without a fungicide, each trial having 8–20 commercial hybrids. Fungicide application was done between V8 and V12 stages (eight and twelve fully expanded leaves, respectively), using a commercial fungicide mix of azoxystrobin and cyproconazole. Average yield variation across sites ranged from 4359 to 12,101 kg ha−1, and fungicide use produced an average positive yield increase of 472 kg ha−1 (or 5.8 %). The yield increase varied from no response to 1282 kg ha−1 across sites, and was not correlated to the site yield. Fungicide application explained 1.9 % of the total yield variation, higher than its interaction with either site or genotype (1.1 and 0.1 % of total yield variance, respectively). Mean temperature from sowing to V14 (fourteen fully expanded leaves) helped explain the crop yield response variation to fungicide application across sites, increasing by 138 kg ha−1 °C−1 in response to higher mean temperature (explored temperatures from 21.9 to 26.4 °C). Our results illustrate the relevance of fungicide applications to reduce yield gaps, where described predictors can help farmer optimize this decision.

A synthesis‐analysis of winter oilseed rape yield response to planting density under intensive cropping system in Yangtze River Basin

AbstractOptimal yield is dependent on the collocations between plant population and individual growth. High plant population for direct‐sown winter oilseed rape would be a common method to achieve high yield under intensive cropping systems. We investigated the oilseed rape (Brassica napus L.) yield response to planting density while considering the productivity environment, nitrogen (N) fertilizer, and sowing date. A synthesis‐analysis was conducted by collecting the density–yield data in the field experiments of oilseed rape from 2000 to 2019 in China. The population yield response to different planting density levels could be described by a quadratic model, with a threshold value of 45–60 plants m−2. High planting density had no remarkable influence on the attainable population yield due to the decreasing individual potential yield. The population yield increment capacity by the increasing planting density was higher in medium yield environment (i.e., average yield at 1500–2500 kg ha−1). The planting density presented a remarkable effect on population yield after the N limitation was relieved. Increasing planting density at 104 plants per hectare was equivalent to applying 1.17 kg N fertilizer on population yield, ranging from 0.42 to 4.76 kg under different yield environment levels. Yield loss caused by unsuitable sowing date (especially for the late sowing) could be compensated by increasing planting density. Planting density played a crucial role in adapting other management practices. Optimizing the allocation of plant population and individual growth, and establishing target plant phenotype under high planting density would help achieve high population yield.

RELATIONSHIP BETWEEN HIGH-TEMPERATURE STRESS AND KEY PHYSIO-CHEMICAL, REACTIVE OXYGEN SPECIES AND ANTIOXIDANTS IN SPRING MAIZE HYBRIDS UNDER SEMI-ARID CONDITIONS

High-temperature stress is one of the hurdles to achieving self-sufficiency and sustainability in maize production globally. The current experimental study was executed to identify the best suitable maize hybrids for heat-prone areas based on their performance. During spring 2020 & 2021, hybrids were sown under two stress conditions (a) control sowing and (b) late sowing. Kernel yield and related characteristics varied significantly among maize hybrids across both situations (P<0.05). Under High-temperature stress, correlation analysis uncovered a positive relationship between kernel yield and chlorophyll a (r = 0.77**, 0.54**), chlorophyll b (r = 0.72**, 0.66**), net photosynthetic rate (r = 0.71**, 0.67**), proline contents (r = 0.59*, 0.54**), hydrogen peroxide (r = 0.54*, 0.17NS), thousand kernel weight (r = 0.71*, 0.38*). Principal component and biplots analysis unveiled that the first four principal components accountable for 78.0% of the total variability among hybrids, with days to 50% silking, plant height, number of kernels per ear, kernel yield, net photosynthetic rate, hydrogen peroxide, malondialdehyde, and catalase as the primary sources of variation. Agglomerative Hierarchical Clustering (AHC) categorizes indigenous and multinational maize hybrids into three classes under stress treatments. The cluster analysis further revealed that indigenous hybrids, particularly YH-5395, YH-5482 and YH-5427 were the most heat tolerant and productive hybrids while YH-5404, P-1543 and JPL-1908 were among the most heat susceptible ones. Consequently, these hybrids are recommended for widespread cultivation, particularly in regions prone to high temperatures.

Tillage Systems Effect on Wheat Yield in the Saïs Region of Morocco

Morocco is facing a significant threat to food grain production due to climate change, with an important incline in temperature and a decline in precipitation. Conservation agriculture (CA) is an important tool to confront soil fertility depletion and the adverse effects of climate change. The objective of this work was to compare and evaluate the impact of four cultivation techniques (no-till: NT, minimum till: MT, chisel ploughing: CP and deep ploughing: DP) on certain physiological and agronomic parameters of bread wheat. In this context, an experiment was fielded at the experimental station of Douyet of the National Institute of Agronomic Research of Meknes, Morocco during the 2019-2021 cropping seasons. The experimental design was a complete randomized block, with three replications. Results showed that the stomatal conductance and chlorophyll content revealed a significant effect in the end of flowering stage but no significant effect showed in the heading stage. NT showed the highest grain yield compared with other practices (DP, CP and MT). The decrease in grain yield registered in the first year was related to late sowing and to the drought stress caused by a low rainfall (135 mm) compared to the second year (377 mm). Moreover, the WUE in the NT obtained a higher value (6.36 kg ha^-1 mm^-1) followed by CP (5.14 kg ha^-1 mm^-1), DP (4.99 kg ha^-1 mm^-1) and MT (4.89 kg ha^-1 mm^-1). While in the second year, the NT registered a higher WUE (10.05 kg ha^-1 mm^-1) than other cultivation practices DP (8.72 kg ha^-1 mm^-1), MT (8.41 kg ha^-1 mm^-1) and CP (8.31 kg ha^-1 mm^-1).

EVALUATION OF GENETIC VARIABILITY AND HERITABILITY OF WHEAT GENOTYPES UNDER LATE SOWING EFFECTS

(Triticum aestivum) is staple food for more than half of the world population. In the present study 10 genotypes were sown to check the wheat genotype's genetic variability and under late sowing. Exploration occurred at the Department of Agriculture, BZU, Bahadur sub-Campus, Layyah during 2019-2020. The investigation was spread out in understanding to Randomized Complete Block Design (RCBD). Perceptions on various Traits of wheat Genotype to check the late effect were recorded from 3 plants of every wheat genotype. Information was recorded to evaluate the late sowing effect (Plant Height, Spike Length, No. of Spikelet’s, No. of Tillers, Grain yield per plant and Biological Yield). FSD-83 show great resistance against late sowing and their traits are less affected by late sowing. FSD-83 has high grain yield than other varieties in late sowing. Each trait of FSD-83 resists better against late sowing than different varieties. Extreme yield trait of LY-73 effects by late sowing. Information indicated that late sowing decreases grain production of each wheat Genotype. So, it is recommended that the breeder should sow wheat genotypes an ideal time on 25 October – 15 November. Present discoveries show that each trait of wheat genotype especially grain yield, affects late sowing and decreases grain yield of every wheat genotype, but FSD-83 resist better and shows less effect of late sowing on grain yield.

Phenotypic characterization of wheat germplasm for heritability and dissection of association among post anthesis traits under variable sowing dates

BackgroundThe world's main crop for producing staple foods is wheat. In South Asia's cotton-wheat cropping system, however, a late cotton harvest causes a delayed wheat planting, which causes significant production losses. Therefore, this study investigated genetic diversity among wheat genotypes for late sowing. Additionally, associations between several yield-related parameters were discovered, along with their direct and indirect implications on the choice of the best genotypes suitable for late planting. MethodsTwenty wheat genotypes/advance lines were evaluated under two sowing times, i.e., normal sowing and late sowing for two consecutive years (2019–2021). Data regarding post anthesis traits were collected. ResultsThe findings showed that planting dates and genotypes substantially (p < 0.05) impacted all characteristics. Genotype ‘9622’ proved consistent for grain yield by showing the lowest reduction under late sowing. Similar to this, assessments of heritability, correlation, and path coefficients showed that heredity and association strength varied with various sowing dates. Number of spikelets per spike, spike length and biological yield showed the highest correlation and direct and indirect effects on grain yield. Association among traits, and the performance of different genotypes under normal and late sowing was also confirmed by biplot analyses, which grouped the genotypes based on their variation for different traits. ConclusionIn conclusion, late sowing reduced yield and changed association among the studied traits, probably due to terminal heat stress. Therefore, selection criteria must be evaluated separately in selecting genotypes adoptable to late sowing and other varying environmental conditions.

Modeling adaptation of sorghum in Ethiopia with APSIM—opportunities with G×E×M

Sorghum is an important food and feed crop in the dry lowland areas of Ethiopia. Farmers grow both early-sown long-duration landraces and late-sown short-duration improved varieties. Because timing and intensity of drought stress can vary in space and time, an understanding of major traits (G), environments (E), management (M), and their interactions (G×E×M) is needed to optimize grain and forage yield given the limited available resources. Crop simulation modeling can provide insights into these complex G×E×M interactions and be used to identify possible avenues for adaptation to prevalent drought patterns in Ethiopia. In a previous study predictive phenology models were developed for a range of Ethiopian germplasm. In this study, the aims were to (1) further parameterize and validate the APSIM-sorghum model for crop growth and yield of Ethiopian germplasm, and (2) quantify by simulation the productivity-risk trade-offs associated with early vs late sowing strategies in the dry lowlands of Ethiopia. Field experiments involving Ethiopian germplasm with contrasting phenology and height were conducted under well-watered (Melkassa) and water-limited (Miesso) conditions and crop development, growth and yield measured. Soil characterization and weather records at the experimental sites, combined with model parameterization, enabled testing of the APSIM-sorghum model, which showed good correspondence between simulated and observed data. The simulated productivity for the Ethiopian dry lowlands environments showed trade-offs between biomass and grain yield for early and late sowing strategies. The late sowing strategy tended to produce less biomass except in poor seasons, whereas it tended to produce greater grain yield except in very good seasons. This study exemplified the systems approach to identifying traits and management options needed to quantify the production-risk trade-offs associated with crop adaptation in the Ethiopian dry lowlands and further exemplifies the general robustness of the sorghum model in APSIM for this task.

Genetic dissection of marker trait associations for grain micro-nutrients and thousand grain weight under heat and drought stress conditions in wheat.

Wheat is grown and consumed worldwide, making it an important staple food crop for both its calorific and nutritional content. In places where wheat is used as a staple food, suboptimal micronutrient content levels, especially of grain iron (Fe) and zinc (Zn), can lead to malnutrition. Grain nutrient content is influenced by abiotic stresses, such as drought and heat stress. The best method for addressing micronutrient deficiencies is the biofortification of food crops. The prerequisites for marker-assisted varietal development are the identification of the genomic region responsible for high grain iron and zinc contents and an understanding of their genetics. A total of 193 diverse wheat genotypes were evaluated under drought and heat stress conditions across the years at the Indian Agricultural Research Institute (IARI), New Delhi, under timely sown irrigated (IR), restricted irrigated (RI) and late sown (LS) conditions. Grain iron content (GFeC) and grain zinc content (GZnC) were estimated from both the control and treatment groups. Genotyping of all the lines under study was carried out with the single nucleotide polymorphisms (SNPs) from Breeder's 35K Axiom Array. Three subgroups were observed in the association panel based on both principal component analysis (PCA) and dendrogram analysis. A large whole-genome linkage disequilibrium (LD) block size of 3.49Mb was observed. A genome-wide association study identified 16 unique stringent marker trait associations for GFeC, GZnC, and 1000-grain weight (TGW). In silico analysis demonstrated the presence of 28 potential candidate genes in the flanking region of 16 linked SNPs, such as synaptotagmin-like mitochondrial-lipid-binding domain, HAUS augmin-like complex, di-copper center-containing domain, protein kinase, chaperonin Cpn60, zinc finger, NUDIX hydrolase, etc. Expression levels of these genes in vegetative tissues and grain were also found. Utilization of identified markers in marker-assisted breeding may lead to the rapid development of biofortified wheat genotypes to combat malnutrition.

Sowing date influence on the soybean tolerance to defoliation at the beginning of pod formation

Late sowings anticipate flowering and decrease the soybean vegetative plasticity. These changes may limit the ability of plants to tolerate leaf area losses. The objective of this research was to evaluate the sowing date effect on soybean tolerance to defoliation at the beginning of pod formation. The experiment was set in Lages (Santa Catarina State, Brazil) during the 2016/2017 growing season. Two sowing dates were tested: November 2, 2016 (preferential) and December 15, 2016 (late). Five levels of defoliation (0%, 17%, 33%, 50% and 67%) of cultivar NA 5909 RG were imposed at the R3 growth stage. Grain yield showed a quadratic response to defoliation, ranging from 4,313 to 6,478 kg ha-1 in the preferential sowing date and from 3,374 to 4,443 kg ha-1 in the late sowing date. The plants tolerated up to 45.6% of defoliation in early sowing and 55.8% in late sowing, without yield losses, in comparison to the control. The highest level of defoliation reduced grain yield by 26.9% and 13.4% in early and late sowings, respectively, compared to the control. The delay of sowing date did not increase the sensitivity of cultivar NA 5909 RG to defoliation at the beginning of pod formation.

Yield and Quality Changes in Barley Genotypes During High Temperature Stress Caused by Late Sowing

In achieve yield sustainability, it is important to cultivate barley varieties that are resistant to the heat and drought stress conditions carried on by global climate change. Barley is one of the significant cultivars that is negatively affected by global climate change due to its low tolerance to heat stress. Late sowing was employed to ensure that plants were exposed to heat stress in order to evaluate the agronomic performance of barley genotypes under high temperature stress. The late sowing process was carried out in February 2019 and 2020 years. Heading time, physiological maturity, plant height, chlorophyll content (SPAD), normalized difference vegetation index (NDVI), grain weight, protein content, test weight, ground cover (Canopeo) and leaf area index (LAI) were investigated using three local varieties, three advanced lines, and two standard barley varieties. Precipitation of more than 450 mm throughout the vegetation period in both years, as well as sufficient water storage in the soil before to the vegetation period, allowed the growth phase to be effectively examined under heat stress. There were significant differences among genotypes in all traits except plant height and NDVI. Except for physiological maturation and protein ratio, the genotype x environment interaction had an effect on all characteristics. This demonstrated that, in the absence of water stress, mainly high temperature effects had an impact on yield. Among the advanced lines examined, the DZ21-17 genotype succeeded in terms of staying green, being early, increasing chlorophyll content, and increasing grain weight. Local varieties maintained productivity in heat stress by increasing leaf area, while grain yield potential stayed behind standard varieties and advanced lines. Local cultivars had the advantage of fast ground cover and having a high growth rate. It has been determined that barley genotypes with high plant height and grain weight will have a high yield potential under conditions of heat stress.

The Impact of the Sowing Time on Peanuts Yield`s Components in Marginal Sandy Soils in Southern Oltenia, Romania

Marginal sandy soils are frequently characterized by low fertility, low organic matter, moderate to high acidity and low cationic exchange capacity, limiting the options of smallholding farmers for various crops. To investigate the impact of the sowing time on grain yield, yield components, protein and oil content of peanuts cultivated in marginal sandy soils in Southern Oltenia, Romania, a bifactorial experiment in a randomized complete block design with three replications was conducted during 2015-2017 at the Research Development Station for Plant Culture on Sands Dăbuleni. The first factor was sowing time (the 25th April as early sowing and the 5th May as late sowing) and the second factor was peanut cultivar (Dăbuleni, Viorica, Viviana). According to the results of the experiment the sowing time had significant impact on the pods number per plant, the production of pods and the grain oil content. Analyzing the interaction between the sowing time and the cultivar there were significant differences only in the pod number per plant in 2015 and the production of pods in 2016. In all peanut’s genotypes studied, early sowing led to higher yields of pods compared to late sowing, probably due to the shortening of the vegetation period of the crop by late sowing on the 5th May, which led also to less dry matter and lower oil content accumulated in peanut grains. Therefore, the results suggested that early sowing time is the most recommended for peanuts growth and quality yield in sandy marginal areas.

Variation of plant height and ear insertion height traits in short-season maize hybrids under the optimal and late sowing dates

Topicality. In light of the intensification of agriculture towards more rational utilisation of land resources and the growing season, given the importance of stubble and postcut fodder maize crops in fodder production and maize adaptability to the conditions of the Steppe zone, it is important to study the growth processes of maize under late sowing. Namely, the study of the influence of late sowing date on such traits as plant height and insertion height of the first productive ear for early ripening hybrids, the share of which in maize grain production is increasing. Purpose. To establish the most stable hybrid combinations by studying the variability of plant height and ear insertion height in early ripening maize hybrids under two sowing dates. Methods. Hybridization was used for developing hybrid material; laboratory and field method – to determine morphobiological traits of maize hybrids; measuring weight - to determine metric traits of plants; mathematical and statistical method – to determine the reliability of results, indicators of trait variability, and the correlation of traits. Results. The study of early ripening maize hybrids developed by crossing the most common germplasms under two sowing dates revealed that hybrids of heterotic models Iodent×Flint and Iodent×Mix had stably high values of the plant height trait at both sowing dates; hybrids of heterotic models Iodent×Flint and Iodent×Mix and Mix×Flint had stably high values of the insertion height of first productive ear at both sowing dates. Conclusions. We have identified the hybrid combinations DK4173SVZM×DK367, DK4172×DK367, MS381MV×DK367, MS555×DK367 (heterotic model Iodent×Mix), and DK4173SVZM×DK2073 (heterotic model Iodent×Flint), which were characterised by stably high values of the plant height trait, as well as the hybrid combinations DK4172×DK4538 (heterotic model Iodent×Flint), DK4172×DK367 (heterotic model Iodent×Mix), and DK2659×DK4538 (heterotic model Mix×Flint), which were characterised by stably high values of the insertion height of first productive ear at both sowing dates. The correlation between plant height and the ear insertion height of maize hybrids was confirmed for both sowing dates in all heterotic models studied. Key words: common maize, breeding, prematurity, plant height, ear insertion height, sowing dates, line, single-cross hybrids

Effect of Sowing Dates on Seed Yield Attributes in Indian Mustard

The effects of early and late sowings were studied on Indian mustard cultivars. During the years 2021-22, the 8 genotypes were cultivated in RBD with 3 replications on three sowing dates: September (D1 ), October (D2 ), and November (D3 ) at SST, IARI, and New Delhi. Sowing dates were found to be significant for all of the characters, although genotypes and their interactions were only significant for a no. of seeds per siliqua studied. The results revealed that the timely sown condition (D2 ) was found to be better for all genotypes. Among the eight genotypes, JC-33 had a maximum no. of seeds per siliqua in timely sown condition (D2). It was discovered that the sowing date influenced yield characteristics significantly. As the sowing date was extended, the seed yield was found to decline dramatically.

Influence of Different Planting Dates on the Quantitative and Qualitative Traits of Soybean (Glycine max L.) under Coastal Environments

A pot experiment was conducted in spring season during 2018 under the coastal environmental conditions of Lasbela University of Agriculture, Water and Marine Sciences to examine the effect of planting date on seed yield and quality traits of soybean. In this study three sowing dates (T1 = Mid-January, T2 = Early February and T3 = Mid- February) were tested against three soybean varieties (NARC-I, NARC-II and Rawal) in CRD with four replicates. The results revealed that the effect of sowing dates on seed germination percentage was non-significant (p&gt;0.05) but significant (p&lt;0.05) on rest of the growth, yield and other quality traits of soybean. Similarly, varietal effect on all the growth, yield and its contributing traits were significant (p&lt;0.05). Apart from germination percentage (79.79, 80.33, 81.35 %), significant difference between Mid-January, Early February and Mid-February sowing was determined for plant height (46.89 cm), pods plant-1 (74.79), pod length (4.90 cm), seed weight plant-1 (6.15 g), total biomass weight plant-1(22.91 g), harvest index (26.95 %), number of nodules plant-1 (15.09), root length (8.90 cm), protein content (44.11 %) and oil content (23.64 %), respectively. In case of soybean varieties, NARC- I, NARC-II and Rawal showed significant variation for seed germination (85.35 %), plant height (49.68 cm), pods plant-1(82.07), pod length (5.15 cm), seed weight plant-1 (6.27 g), plant biomass weight plant-1 (23.16 g), harvest index (28.33 %), number of nodules plant-1 (15.87), root length (9.36 cm), protein content (43.36 %) and oil content (23.99 %), respectively. It was concluded that sowing of soybean in first fortnight of February resulted in optimistic results in relation to seed weight plant-1. Too early (Mid-January) or too late (Mid-February) sowing showed similarity (p&gt;0.05) for pods plant-1 and seed weight plant-1. Insignificant (p&gt;0.05) difference between early February and mid- February sowing was observed for pod length, harvest index, nodules plant-1 and root length. On the basis of overall performance, variety NARC-I ranked 1st, NARC-II ranked 2nd and Rawal ranked 3rd; while interactive effect of NARC-II × Early- February sowing maximized seed weight plant-1; while variety Rawal × Early-February sowing resulted in maximum biomass weight. Similarly, interaction of variety ‘NARC-II’ × Mid-February sowing resulted in highest protein content; while interactive effect of variety ‘NARC-II’ × Early-February sowing resulted in highest oil content.

The role of genetic and biological features of plants in the formation of the sugar beet harvest at different sowing times

This article studied the influence of sowing dates of various biological forms of sugar beet on the productivity of root crops in specific soil and climatic conditions. The role of sowing dates on seed germination, the dynamics of the formation and drying of sugar beet leaves, the number of functioning leaves during the growing season, as well as the dynamics of the growth of the leaf surface area of sugar beets depending on varietal characteristics and sowing dates are shown. Both the lack and the excess of any factor negatively affect the productivity of plants. Therefore, when developing agricultural techniques for crop cultivation, it is important to take into account the timing of sowing, the specifics of the action of mineral fertilizers, the genetic properties of hybrids, climatic and weather conditions, soils, states of organogenesis, phases and interphase periods of plant growth and development. Operational management of the process of crop formation, taking into account varietal characteristics, during the growing season by selecting the appropriate agrotechnical measures and the terms of their implementation should be carried out taking into account the state of crops and meteorological conditions. The scientific basis for agrotechnical measures is the theory of the dynamics of crop formation. It was established that during the early sowing period, the reserves of productive moisture and nutrient reserves in the soil in the first half of the growing season are greater than in the later ones, which ensures the rapid development of the root system, the growth of the leaf surface, the increase in the mass of root crops and the accumulation of sugar in them. The highest yield of root crops and sugar yield per hectare was obtained when sowing triploid hybrid Okhtyrskyi and diploid hybrid ICB 0902 during the first sowing periods. Sowing beets five days later reduced yield by 3.8 t/ha and sugar content by 0.1 %. Late sowing dates sharply reduced the yield and sugar content of root crops. Key words: sugar beet, germination, yield, oneseeded, sugar content, sugar collection.