Early-sown Crops Research Articles

Effect of Foxtail Millet Cultivars on Yield and Yield Attributes under Different Sowing Windows

The investigation conducted at the Agronomy Farm, College of Agriculture, Pune, during the Kharif season of 2022 focused on the "Effect of foxtail millet cultivars on yield and yield attributes under different sowing windows." The study employed a split-plot design with sixteen treatments and three replications, involving four sowing dates (26 MW, 28 MW, 30 MW, and 32 MW) and four foxtail millet varieties (SiA 3156, SiA 3085, Suryanandi, and Renadu). The soil, a clay loam with slightly alkaline pH, low nitrogen, medium phosphorus, and high potassium levels, received RDF 60:30:30 N: P2O5: K2O kg ha-1 at sowing. The investigation monitored various growth parameters, including plant height, number of tillers, number of functional leaves, and dry matter accumulation, at different growth stages. The study revealed that early sowing at 26 MW significantly influenced plant height, number of tillers, and dry matter production, favoring greater vegetative growth. The Renadu variety consistently exhibited superior performance in plant height, tiller count, and dry matter accumulation compared to other varieties. Days to 50% flowering and maturity were significantly affected by both sowing dates and varieties, with early-sown crops taking more days to reach these stages. Grain yield, straw yield, and harvest index were influenced by sowing dates and varieties, with the combination of the Renadu variety and 26 MW sowing exhibiting the highest grain yield and straw yield. Renadu also displayed a superior harvest index, emphasizing its suitability for optimal growth and yield. The study recommends sowing foxtail millet on 26 MW or 28 MW, particularly with the Renadu variety, for achieving maximum growth and yield during the Kharif season. The findings highlight the significance of considering both sowing windows and foxtail millet varieties to optimize production in the given agro-climatic conditions of Pune, Maharashtra.

Agroclimatic Indices, Phenology and Growth Response of Clusterbean to Different Dates of Sowing and Varieties

A field experiment was performed to study the effect of different sowing times and varieties on agroclimatic indices, phenology and growth of clusterbean at CCS Haryana Agricultural University, Hisar (Haryana). Experiment was laid out in factorial randomized block design with three replications. Treatments consists of two factors i.e. sowing time and varieties. Three clusterbean varieties i.e. HG 365 (V1), HG 563 (V2) and HG 2-20 (V3) with each sown at three different dates of sowing i.e first (D1), third (D2) and fourth (D3) week of July. Clusterbean variety HG 563(V2), sown in first week of July (D1) resulted in significantly higher accumulation of agroclimatic indices i.e. growing degree days, photo thermal units, heliothermal units and heat use efficiency because the early sown crop had a fully developed normal reproductive phase and took longer time to attain maturity. Similarly, more number of days were taken for emergence, days to 50% flowering, days to 50% pod formation and days to maturity in variety HG 563, sown in first week of July. Significantly higher leaf area index and dry matter accumulation were observed in HG 563 sown on 1st week of July than rest of the varieties and date of sowings.

Effect of Sowing on Population Dynamics of Aphid <i>Myzus persicae</i> (Sulzer) on Cumin

A field experiment was conducted to study the population dynamics of aphid, Myzus persicae (Sulz.) and to see the effect of sowing dates. Cumin variety Gujarat Cumin 4 (GC-4) was grown during rabi 2020-21. The incidence and population fluctuation was dependent on the weather parameters. The incidence initiated in third week of December (51st Standard Meteorological Week-SMW). Initially, incidence was low (6.00 aphids/three umbels) but it gradually increased and reached the peak in last week of January i.e. 5th SMW (115.03 aphids/three umbels). The early sown crop (26th October) had the minimum infestation (68.00 aphid/3 umbels) of aphids and highest seed yield (4.90 q/ ha) was obtained as compared to the late sowing crop on 7th December (106.50 aphids/ umbels) with minimum seed yield (3.10 q/ ha).

Effect of irrigation schedules on productivity, quality and water use of Indian mustard (Brassica juncea) under staggered sowing in Northwest India

A field experiment was conducted during the winter (rabi) seasons of 2019–20 and 2020–21 at the Guru Kashi University, Talwandi Sabo, Bathinda (Punjab), to study the effect of irrigation schedules on different growth, yieldattributing characters, yield, quality and water use in Indian mustard [Brassica juncea (L.) Czern.] in relation to sowing time. Results revealed that, early-sown crop, i.e. 10 October, recorded the higher growth parameters, viz. plant height, dry-matter accumulation, primary branches/plants, secondary branches/plant, and yield-attributing characters, viz. siliquae/plant, seeds/siliqua, siliqua length and 1,000-seed weight of Indian mustard. The crop sown on 10 October gave the highest seed yield (1449 kg/ha) which was significantly higher than the crop sown on 25 October (1,171 kg/ha) and 10 November (643 kg/ha). Oil yield, nitrogen content and protein content were also significantly higher in 10 October sown crop. Early-sown crop, i.e. 10 October, resulted in the 21.2 and 119.5% higher water-use efficiency (7.55 kg/ha/mm) than 25 October (6.23 kg/ha mm) and 10 November (3.44 kg/ha/mm) sown crop. Application of 3 irrigations, viz. at branching, flowering and siliqua-formation stages, resulted in higher plant height, dry matter, primary and secondary branches/plant, siliquae/plant, 1,000-seed weight, stover yield and harvest index in Indian mustard. Three irrigations at branching, flowering and siliqua-formation stages resulted in significantly higher seed yield (1,658 kg/ha), oil content (42.2%), oil yield (699.7 kg) and protein content (22.3%). This treatment resulted in the 23.3% higher water-use efficiency (6.50 kg/ha/mm) than the control (5.27 kg/ha/mm).

Physiology and Yield of Chickpea (Cicer arietinum L.) Genotypes in Response to Different Sowing Dates in Semi Arid Regions of North India

Background: Climate change causes variation in global temperature in last two decades which causes detrimental effects on agricultural crops being grown in arid and semi-arid regions. Chickpea crop sensitive to variation in temperature as the late-sown crop is exposed to high temperatures ( greater than 35°C) at its reproductive stage in the months of February and March and early sown crops is exposed to low temperature ( less than 5°C) at its vegetative stage in December and January so optimum sowing time plays a vital role for overall growth and development of the plants. Methods: The experiment comprising of three sowing dates that is 15th October (early sown condition in Haryana), 15th November (Normal sown condition in Haryana) and 15th December (late sown condition in Haryana) with ten chickpea (Cicer arietinum L.) genotypes namely ICCV 88503, ICCV 92944, HC-1, HC-3, HC-5, H12-64, H13-01, H13-02, H14-01 and H14-04 in randomized block design during Rabi season of 2017-18 and 2018-19 at Pulses Section, Chaudhary Charan Singh Haryana Agricultural University, Hisar Result: Statistically no significant differences in seed yield was recorded between 15th October and 15th November sowing, however, further delay in sowing to 15th December showed significant reduction in seed yield while maximum values for recorded physiological parameters in chickpea genotypes were found in 15th November sowing and minimum in 15th December sowing. Among genotypes maximum physiological parameters and seed yield were observed in H12-64 and H13-01 while minimum were found in H14-04.

Modelling the factors affecting the spatiotemporal distribution of cabbage stem flea beetle (Psylliodes chrysocephala) larvae in winter oilseed rape (Brassica napus) in the UK.

Cabbage stem flea beetle (CSFB; Psylliodes chrysocephala L.) management in oilseed rape (Brassica napus L.) has become an urgent issue in the absence of permitted and effective insecticides. Understanding the meteorological and management factors affecting their population dynamics has become critical to the development of pest management strategies. The spatio-temporal changes in CSFB larval populations were assessed both in autumn and spring, in the UK from 2003 to 2017 (a period encompassing pre-and post-neonicotinoid insecticide restriction). After the neonicotinoid ban in 2013, the number of larvae both in autumn and spring increased 10-fold in the UK. When neonicotinoids were available, later sown crops contained fewer larvae than early sown crops, and bigger fields had fewer larvae than smaller fields, whereas after the ban, bigger fields tended to have more larvae than smaller fields. Wet and mild/hot Septembers were related with higher numbers of larvae when neonicotinoids were available and with lower larval numbers after the neonicotinoid ban. Low temperatures in December and January combined with high rainfall were related with high numbers of larvae in spring both before and after the neonicotinoid ban. This study will help to produce decision support systems that allow future predictions of regional CSFB population changes and will help growers and consultants to adjust their management methods to reduce the risk of high infestations. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of Sowing Window and Phosphorus Levels on Growth and Yield of Summer Fodder Cowpea

Background: Cowpea [Vigna unguiculata (L.) Walp.] has emerged out as a potential crop for meeting the requirement of high quality fodder to fast expanding cattle population. There is a large gap between the demand and supply of green fodder during the lean period which can be narrowed down through the agronomic approaches. Among them, time of sowing and fertilizer application are considered to be the most important factors determining the production potential of the crop. Keeping this in view, the present investigation was taken up in order to find out the optimum time of sowing along with the optimum dose of phosphorus for the production of fodder cowpea. Methods: The present experiment was undertaken during summer, 2019 on sandy loam soils of dryland farm, S.V. Agricultural College, Tirupati. Three time of sowing viz., I fortnight (FN) of January, II FN of January and I FN of February assigned to main plots and four levels of phosphorus viz., 0, 20, 40 and 60 kg P2O5 allotted to subplots with three replications were maintained under split plot design. Result: The plant height, number of leaves plant-1, number of branches plant-1, dry-matter production and number of nodules plant-1, leaf to stem ratio and green fodder yield were higher with early sown crop i.e. I FN of January. Application of 60 kg P2O5 ha-1 resulted in significant improvement in the growth parameters, yield attributes and yield of fodder cowpea, while the lowest were recorded under control conditions (0 kg P2O5 ha-1). The interaction between time of sowing and phosphorus levels influencing the above parameters was found to be non-significant. In conclusion, the present investigation revealed that fodder cowpea gives optimum green fodder yield with high nutritional quality on sown during I FN of January with 60 kg P2O5 ha-1.

Relationship of some insect pests of roselle with weather parameters in Makurdi, Nigeria

The population dynamics of three insect species namely: Monolepta thomsoni, Nisotra sjostedti, and Dysdercus volkeri along with their correlation with weather factors were studied during the 2016 cropping seasoning Makurdi, Benue State, Nigeria. Insect count was done within a 1m by 1m area for 21 weeks. M. thomsoni and N. sjostedti populations peaked at 9 WAP, while D. volkeri peaked at 21 at pod maturity. M. thomsoni and N. sjostedti strongly linked with early crop relative humidity. M. thomsoni associated favourably with rainfall and relative humidity in the late harvest, but not maximum temperature. D. volkeri was positively correlated with sun radiation, maximum temperature, and relative humidity in early-sown crops. Positive and significant association between D. volkeri and maximum temperature in late crop. N. sjostedti did not link with late-sown crop weather. This study's result can be used to forecast insect pest damage, which can aid with pest management.

Effect of Sowing Dates and Varieties of Wheat Crop (Triticum aestivum L.) on Growth and Productivity under Changing Climate

The field experiment was conducted at Crop Research Station Masodha, Acharya Narendra Deva University of Agriculture & Technology, Kumarganj, Ayodhaya (U.P) during Rabi season November, 2017-April, 2018. In the field environment, the growth of wheat was greatly influenced by temperature changes associated with sowing dates. The productivity of wheat is highly vulnerable to climate change. The experiment laid out in Split plot design (SPD) with 3 replication and four different dates of sowing (05th November,25th November, 15th December, 05th January) in a main plot against six varieties of the Wheat crop (HD-3086, HS-562, HI-1544, WR-544, MACS-6222 and HD-2967) in sub plot.. Growth parameters were higher in early sown crops as compared with late sown wheat crops. Among varieties HD-3086 sown on 25th November obtained the highest growth parameter as compared to HS-562, HD-2967, HI-1544, MACS-6222 and WR-544. Growth and yield potential of crop or variety are the outcomes of genomic, environmental and agronomic interactions. Due to the reduction in tillering period and increased risk of hot weather during grain filling, late planting results in a linear reduction in wheat grain yield. it may be concluded that optimum sowing time of wheat crop is 25th November as compare to late sown wheat. Among the variety HD-3086 is the most promising variety.

Effect of sowing date, irrigation and mulch on thermal time requirement and heat use efficiency of maize (Zea mays L.)

The field experiments was carried out for three years (2015 to 2017) at the Research Farm, Department of Climate Change and Agricultural Meteorology, Punjab Agricultural University, Ludhiana with maize variety PMH-1 sown on three dates (D1-Third week of May, D2-Second week of June and D3- First week of July) under two irrigation regimes (I1 = IW:CPE 1.0 and I2 IW:CPE 0.75) and mulch application (M1: straw mulch @ 5 tha-1 and M2: without mulch) in a split plot design.Results revealed that the early sown crop(third week of May) took higher number of days and heat units to attain various phenophases. Maize variety PMH-1 consumed maximum heat units of 1952oC days for maturity under early sown condition. The heat use efficiency was highest (3.04 kg ha-1oCday-1)for the crop sown during June. Among irrigation regimes, the HUE was higher (2.89 kg ha-1oC day-1) in IW: CPE = 0.75 level of irrigation ascompared to IW: CPE = 1.00 (2.81 kg ha-1oCday-1) and higher HUE was obtained with mulch application (M1) (2.92 kg ha-1oCday-1) as compared to without mulch (M2) (2.76 kg ha-1oCday-1). The sowing of maize crop during second week of June with irrigation of IW: CPE 0.75 under mulch application have been found to be the most efficient for heat utilisation.

Thermal and radiation environments for assessing crop-weather relationship of soybean in eastern Madhya Pradesh

A field experiment was conducted during with three sowing dates (23 June, 8 July and 23 July) with three varieties (JS 20-29, JS 20-34 and JS 97-52) kharif season of 2016 and 2017 at Jabalpur in eastern Madhya Pradesh for assessing crop weather relationship in soybean through thermal and radiation environments. The results revealed that early sown crop attained more accumulated heat units, and yield decreased with delay in sowing. The maximum and minimum temperatures during reproductive stage were positively correlated with seed yield while negatively associated with vegetative and pod development stages. Photosynthetic active radiation absorption (APAR) was maximum in June sowing in semi-determinate JS 97-52 variety at pod formation stage. Maximum leaf area index (LAI) exhibited in June sown for JS 97-52 variety during pod formation stage. Seed yield increase with increased in APAR and LAI during pod formation stage. Season length difference between normal and actual crop maturity period increased with the decrease in GDD thereby suggesting a decline in yield due to shortening of crop growing period.

Effect of planting time and plant growth habits on phenological, physiological traits and associated with seed yield in African sarson (Brassica carinata)

An experiment was conducted during two consecutive years to study the effect of planting times (15 October, 5 November and 25 November) and cultivars differing for growth habits (BJC-13-1, BJC-13-2, BJC-13-3, BJC-13-4) newly developed determinate type and (PC-5 indeterminate variety) on phenology and physiological traits of African sarson (Brassica carinata A. Braun). The experiment was laid out in split plot design with three replications keeping planting times in main plot and genotypes in sub-plots. Planting time had a significant influence on both phenology and physiological traits of African sarson. The early sown crop took less number of days (66) for flowering while late sown crop took more number of days (79). There was drastic reduction in flowering period (20.8days), siliquing duration (23.3days) and reproductive phase(27.2days). Early planted (15 October) cultivars intercepted more PAR, higher LAI and SPAD-chlorophyll values resulting in higher yield. The interactive effects of planting dates and the cultivars were significant (p < 0.05) for most of the features, which showed variable trends for the changes in the cultivars in response to planting dates. In all the cultivars, there was considerable deterioration in most of the studied traits due to delayed planting. Seed yield had positive association with siliquae duration (0.436), reproductive phase (0.426), SPAD (0.540*) and LAI (0.701**) with first planting (15 October) whereas with late planting (5 November) correlation existed between seed yield and LAI (0.073) and PAR interception (0.086) while with only flowering duration (0.772**) with 25 November sowing.

Relationship of Agro-Meteorological Indices with Cotton Yield Under Varied Pre-Sowing Irrigation Levels, Sowing Dates and Time of First Irrigation in North-Western India

ABSTRACT Irrigation water scarcity during the very high rate of evapotranspiration period (during May and June) is a major concern for cotton production in north-western India. So, an experiment was planned to study the response of cotton to levels of pre-sowing irrigation, different times of sowing, delay in first irrigation and different agrometeorological indices (AMI). Cotton growth and yield attributes and AMI for different phenophases were poor under shallow pre-sowing irrigation and resulted in a reduction in seed cotton yield (SCY) significantly by 14.4–15.7% as compared to heavy pre-sowing irrigation. Timely sown cotton achieved maximum crop growth and yield attributes and AMI as well as SCY over the late sown crop. Late sown crop resulted in more than 40% yield reduction. Cotton crop that received first irrigation at 4 weeks after sowing (WAS) recorded significantly higher SCY along with higher growth and yield attributes and AMI. A delay in first irrigation from 4 WAS to 6 WAS resulted in the reduction of 15% SCY. SCY was significantly correlated with accumulated growing degree days (GDD), phenothermal index (PTI) and helio-thermal units (HTU) with higher correlation coefficients. Hence, higher AMI, SCY and heat use efficiency (HUE) were achieved from early sown crop with heavy pre-sowing irrigation and first irrigation at 4 WAS.

Plant nitrogen status at flowering and kernel set efficiency in early- and late-sown maize crops

• We studied plant N status and kernel set efficiency (KSE) in contrasting sowing dates. • Plant N status at R1 was determined using SPAD readings in ear leaf-blade. • A boundary function analysis was performed to quantify the direct effects of plant N status on KSE. • Plant N status effect on KSE was recorded in late-sown crops at low plant growth rate (PGR). • Plant N status effect on KNP was regulated by prolificacy expression at high PGR in early-sown crops. In maize ( Zea mays , L.) genotypic variability in the relationship between total kernel number per plant (KNP) and plant growth rate (PGR) during the period bracketing silking (R1 ± 15 d), and in kernel set efficiency (KNP PGR −1 , KSE) have been widely documented. Nitrogen supply (N s ) affects PGR and hence KNP (i.e. indirect effect on KNP), but reports on a direct N effect on KNP PGR −1 are still contradictories. Moreover, recent studies have documented that prolificacy (the number of ears per plant) was cancelled out in N-limited plants despite of their high PGR. Additionally, PGR can be differentially affected by environmental conditions (e.g. sowing dates) through indirect effects on plant size or directly, which could determine changes on KSE. Field experiments were carried-out in Paraná (31° 48' S, 60° 32' W), Argentina, during two growing seasons (2014−15 and 2015−16). Two single cross hybrids were sown in two sowing dates (early: September and late: December), with three N fertilizer rates (0, 90, and 270 kg N ha −1 ) at three plant densities (5, 7 and 9 pl m −2 ). The effects of plant N status and plant size on KNP, KSE and prolificacy were study for a wide range of PGR and relative PGR (rPGR). Plant N status was estimated by using SPAD measurements on the ear-leaf blade at R1. Ranges of lower, mid and higher PGR (absolute and relative values) and SPAD units were established using 33rd and 66th percentiles. Curvilinear functions were fitted to kernel number at the apical ear (KN E1 ) vs. PGR and KNP vs. PGR and boundary functions were also fitted to calculate the unexplained variance (i.e. residuals) of these functions, indicative of direct plant N status effects on KSE. Residuals of KN E1 vs. PGR relationship decreased with increases in plant N status up to a threshold value of 46.8 SPAD units (R 2 = 0.75, P < 0.001). Prolificacy was expressed for plants with SPAD units greater than 50 and residuals of KNP vs. PGR relationship decreased with increases in SPAD units only in prolific plants of early-sown crops (R 2 = 0.55, P < 0.10). The analysis of KNP vs. PGR and KNP vs. rPGR allowed us to elucidate the direct effect of plant N status on KSE under a wide range of environmental conditions, especially those promoting by sowing date x plant density x N rate.

Optimizing sowing date for peanut genotypes in arid and semi-arid subtropical regions.

Peanut (Arachis hypogea L.) is an important nut crop extensively grown in rainfed regions of Pakistan. The crop requires low inputs; thus, could grow successfully under diverse environmental conditions. Due to pegging ability, peanut grows aggressively in sandy and sandy-loam soils. However, it has not introduced to Thal region of southern Punjab, Pakistan. A two-year field experiment was conducted to optimize sowing dates for two peanut genotypes (‘BARI-2016’ and ‘NO-334’) in Thal region (Layyah). Similarly, a yield trial was conducted at Chakwal where both genotypes are extensively grown. Five sowing dates (10th April, 1st May, 20th May, 10th June and 30th June) were included in the study. The highest seed yield was obtained with early sown crop (10th April) during both years. Pod formation reduced with increasing atmospheric temperature and no pods were formed on the plants sown on 30th June. Decreased pod formation seemed a major reason for low yield in late-sown crop. The highest yield was observed for the crop sown on 10th April, which was decreased by 40% for the crop sown on 1st May. Genotype ‘BARI-2016’ performed better for seed yield at both locations compared with ‘NO-334’. The results suggested that genotype ‘BARI-2016’ is more adaptive to arid and semi-arid condition under rainfed or irrigated conditions. Sowing peanut at optimum time would increase seed yield in arid and semi-arid regions. Nonetheless, ‘BARI-2016’ can be grown under rainfed and irrigated conditions successfully.

Modelling phenology to probe for trade-offs between frost and heat risk in lentil and faba bean

Extreme temperatures at critical developmental phases reduce grain yield. Combinations of sowing date and cultivar that favour faster development reduce the likelihood of heat stress but increase the risk of frost at critical phases. Current models are unable to predict pulse yield in response to frost and heat, hence our focus on phenology. Our aim was to model phenological variation with sowing date and cultivar for lentil and faba bean against the climatic patterns of frost and heat in 45 Australian locations that spanned 29 °S-41 °S, 11−340 m.a.s.l., and 1−423 km to the coast.For both crops, modelled mean and standard deviation of time to flowering were close to actuals and mean prediction error was below 5%. Comparison of actual and modelled time to flowering returned: r = 0.89 (n = 121, P < 0.0001) and modelling efficiency = 0.73 for lentil, and r = 0.96 (n = 123, P < 0.0001) and modelling efficiency = 0.84 for faba bean.The critical period for yield determination was assumed to span from flowering to 200 °Cd after flowering. Curves fitted to the time-course of frost (< 0 °C) and heat (> 34 °C) probabilities between 1957 and 2018 were used to estimate the date of 10 % frost probability and the date of 30 % heat probability as the boundaries of a frost-heat risk window for the critical period. Out of the 45 locations, 12 were frost-free but with risk of heat, 7 were heat-free but with risk of frost, 3 were frost- and heat-free, and 23 featured a window defined by both frost and heat boundaries. Frost variables discriminated locations more strongly than heat variables. Geographical patterns in thermal regimes emerged that were associated with latitude, altitude and continentality.Realised warming between 1957 and 2018 advanced the time to 200 °Cd after flowering and shortened the critical period in most locations, particularly in early-sown crops. Comparisons of the probability curves of frost and heat between 1957–1985 and 1986–2018 showed, with few exceptions, an asymmetry between delayed late frost (up to 44 d) and earlier heat onset (up to 11 d), with a narrowing of the frost-heat risk window from 46 to 90 d for the period 1957–1985 to 34–64 d for 1986–2018.We identified a dominant role of frost as (i) the main discriminating factor among geographically distinct locations, (ii) the main source of variation of the frost-heat window, and (iii) a putatively increased risk factor with climate change. Adaptation to frost in the critical period for yield is important for pulses despite warming trends. Increased frost tolerance can directly improve yield and indirectly contribute to reduce risk of heat and drought later in the season.

Expansion of maize production in a semi-arid region of Argentina: Climatic and edaphic constraints and their implications on crop management

The Southwestern Pampas (SWP) is a semi-arid region of Argentina with the presence of a widespread caliche layer that limits soil depth. In this region, maize production has recently expanded with scarce information on appropriate management practices. The objective of this work was to provide an agro-climatic and eco-physiological framework of cultural changes of maize cropping systems of the SWP and the main implications of the climatic and edaphic constraints on crop management decisions. The work combined i) public data of regional maize cultivated area for the period 2008–2015 alongside with farmers’ cropping management trends related to sowing dates and plant population density (PPD); ii) on-field experimental data generated from trials in different sites in the SWP sown at different dates, soil depths and PPDs; and iii) a crop water-economy characterization with a probabilistic approach by means of historical climatic series (identifying the El Niño Southern Oscillation (ENSO) phases) in three locations in the SWP across a longitudinal range between the 800 mm and 600 mm isohyets. In the 2008–2015 period, maize area increased five-fold, median sowing date delayed one month and PPD decreased from ca. 7.2 pl m-2 to 3.4 pl m-2. Late-sown crops (7564 kg ha-1; CV = 19%) out-yielded early-sown crops (5888 kg ha-1; CV = 42%) with less variability across environments. Crop evapotranspiration during the cycle (ETacycle) slightly decreased (P50 = 3–32 mm lower) with the delay of sowing, but the proportion of crop evapotranspiration during the reproductive period was significantly higher. ETacycle of late crops did not vary within PPD, but transpiration per plant decreased with PPD and increased in deep soils, especially at low densities. The impacts of sowing date and PPD did not vary among ENSO phases, not supporting the use of ENSO as a decision criterion for maize management in the SWP.

Influence of Sowing Dates, Varying Hybrids of Maize, Zea mays L. and Application of some Insecticides on the Population Density of the Greater Sugarcane Borer, Sesamia cretica Led. (Lepidoptera: Noctuidae)

Study was conducted to investigate effect of sowing dates and varying maize hybrids on population density of S. cretica in farm at Nubariya district, Beheira governorate, Egypt during seasons, 2018 and 2019. Five maize hybrids viz., yellow three ways cross 352, yellow single cross 168, white single cross 122, white single cross 10 and white single cross 128 were tried on three sowing dates viz. 1st April, 15th April and 1st May. Results showed that, population of S. cretica (eggs and larvae) was highest in early sown crop (1st April) while was least in late sown maize (1st May). Also, none of tested hybrids showed immunity or high resistance and S.C.128 hybrid was more resistant to larvae (minimum dead heart percent), while T.W.C.352 hybrid was more sensitive to S. cretica (maximum dead heart percent). Five hybrids can be arranged in ascending order according to their susceptibility (population density of eggs, larvae and infested percentages) as follow: T.W.C.352, S.C.168, S.C.122, S.C.10 and S.C.128. These results were repeated in both seasons study. Five insecticides were tested for their efficacy against S. cretica under field conditions. All treatments were found effective in reducing larvae and protecting plants compared with control. Insecticide Emamectin benzoate was found best, led to minimum number of larvae followed by Chlorantraniliprole and Lufenuron, respectively. While, radiant resulted lowest. On the other hands, Chlorantraniliprole was found best, led to minimum infested followed by Emamectin benzoate.

Wheat yield response to nitrogen from the perspective of intraspecific competition

Agronomic and breeding innovations are essential to support grain production whilst avoiding over-fertilisation and excess reactive nitrogen in some agroecosystems, and chronic under-fertilisation and mining of soil organic matter in others. Based on the well-established negative correlation between yield per unit land area and intraspecific competitive ability, we hypothesised that the yield-nitrogen curve at the centre of fertiliser decisions mirrors the competition-nitrogen curve. A factorial study combining six wheat cultivars, two locations, two sowing dates and four nitrogen rates supported our hypothesis in early-sown crops where intraspecific competition for nitrogen decreased, and competition for radiation and water increased with increasing availability of nitrogen. In late-sown crops, high temperature favouring fast development, short plants and smaller canopies overrode competition for resources as the driver of grain yield. The implication is that genetic and agronomic reduction of intraspecific competition can improve yield per unit available nitrogen.

Evaluation of dry matter production and yield in early-sown wheat using near-isogenic lines for the vernalization locus Vrn-D1

ABSTRACT Wheat (Triticum aestivum L.) grain yield is predicted to decrease in the future because of an increase in air temperature globally. To clarify the effects of the vernalization response gene in wheat to warmer winters, we compared dry matter production and grain yield between spring wheat ‘Asakazekomugi’ and its winter-type near-isogenic line (NIL) carrying different alleles of the vernalization response gene Vrn-D1 under early-, standard-, and late-sowing conditions. Under early-sowing conditions, dry matter production of the NIL carrying the winter allele of Vrn-D1, named Asa (Vrn-D1b), exceeded that of ‘Asakazekomugi’ from mid-March (after stem elongation in Asa (Vrn-D1b)) when the temperatures rose. Tiller number and leaf area index under early-sowing conditions were consistently higher in Asa (Vrn-D1b) than in ‘Asakazekomugi’ from mid-March onward. It was suggested that the early-sown ‘Asakazekomugi’ could not effectively absorb solar radiation to produce dry matter because of the acceleration of stem elongation caused by the Vrn-D1 gene during the cold season. The grain yield of Asa (Vrn-D1b) with early sowing was higher than with standard sowing. In contrast, the grain yield of ‘Asakazekomugi’ was lower in the early-sown crop than in the crop sown at the standard date. These results suggested that the higher grain yield of Asa (Vrn-D1b) than that of ‘Asakazekomugi’ under early-sown conditions could be due to Asa (Vrn-D1b) maintaining high dry matter production after the jointing stage by suppressing acceleration of growth caused by warm conditions after sowing. Abbreviations CGR: crop growth rate; HI: harvest index; LAI: leaf area index; NIL: near-isogenic line; SNP: single-nucleotide polymorphism