Late Maturing Cultivars Research Articles

Yield Yield loss and economic threshold estimates for pod borer (Helicoverpa armigera) in late maturing pigeonpea (Cajanus cajan)

Pod borer [Helicoverpa armigera (Hubner)] is a major biotic constraint to global pigeonpea production. The farmers largely apply synthetic insecticides to control this pest in pigeonpea. The study was conducted to quantify yield losses and estimate economic thresholds for H. armigera. The late maturing cultivar, IPA-203 was infested with different larval densities to determine the insect density-yield loss relationships. The yield response was variable and grain yield declined with increasing larval density from 1–5/plant. Yield loss of 4.56 kg/ha was evident for each unit increase in larval population. Economic threshold estimates indicated that the control measures for pod borer in IPA 203 cultivar should be initiated at an insect density of ≈1 larva/2 plants or at 3% pod damage to avoid the economic crop losses. The damage potential and economic threshold estimates are prerequisite for integrated pest management and reducing production costs (Alves et al. 2017). Present results indicated that relatively low infestations of H. armigera can cause significant yield reduction in pigeonpea hence intensive monitoring and timely control measures are necessary. Based on present economic threshold estimates, the farmers could decide the timing and kind of control measures to be initiated against pod borer in late pigeonpea cultivars to avert the economic losses.

Reevaluation of the degree day base 60°F concept in US cotton (Gossypium hirsutumL.) production

AbstractCotton (Gossypium hirsutumL.) management decisions to abet early growth, fruit set, boll maturation, and harvest preparation are often facilitated by prediction of the date when critical developmental stages are reached. In the United States, growing degree days calculated with a base 60°F (DD60s) are commonly used to predict cotton development. Observations suggest development of modern cultivars differs from previously established guidelines. The objectives were to (1) reevaluate DD60s required for an early, mid‐maturing and late maturing cultivar to reach key growth stages across the US Cotton Belt; and (2) determine if predictions of growth stages are strengthened by optimizing base temperature or including an upper threshold by growth stage. During 2018 and 2019, 22 field trials were established in 10 states. Plant growth stages were monitored weekly and air temperature was computed from interpolated surface observations weighted by a physical, geographic model. Observed DD60s to reach growth stages varied slightly by cultivar and region (≤85 DD60s and ≤130 DD60s, respectively). Required DD60s to reach growth stages exceeded most published ranges. Optimization of base temperature and inclusion of an upper threshold by growth stage did not substantially decrease errors in predicting date of growth stage occurrence. The DD55 and DD55 with an upper threshold of 86°F calculations resulted in slightly lower errors in predicting date of growth stage occurrence than the DD60 calculation. Although guidelines should be updated, it is unlikely slight modification in base temperature or upper thresholds will drastically increase the predictive ability over the DD60 calculation.

Seasonal changes in gas exchange, water and macro-nutrient content differ between Citrus cultivars

Citrus is an evergreen broad-leaved fruit tree including numerous species and cultivars with an extensive global planting area. However, the relationship between physiological parameters and seasonal fruit ripening of different citrus cultivars has not been reported. With the aim to obtain information on this relationship, we selected two late-maturing (Newhall Navel and Ponkan) and two middle-maturing citrus cultivars (Fertile orange and Tarocco) and compared the seasonal patterns of foliar CO2 and H2O gas exchange, leaf water content and macro-nutrient concentrations in leaves and roots. Our results showed that seasonal changes of foliar CO2 and H2O gas exchange and water content greatly differed between cultivars at defined developmental stages, but especially during fruit ripening. For example, in December, the net rates of photosynthetic CO2 fixation (Pn) of the late-maturing cultivars were significantly higher than in middle-maturing cultivars. Seasonal fluctuations of total nitrogen (N), total phosphorus (P), and inorganic phosphorus (Pi), as well as C/N, C/P, and N/P ratios in leaves and roots differed between middle and late-maturing cultivars. These differences were most obvious at fruit ripening compared to other developmental stages and were significantly higher in leaves than in roots. We conclude that seasonal differences in foliar Pn and macro-nutrient contents between leaves of citrus cultivars are largely determined by seasonal fruit ripening. In addition, seasonal changes in root macro-nutrient contents were also affected by seasonal fruit ripening of citrus cultivars. However, this effect was much lower compared to the leaves, but still indicates particular shoot-root interactions during fruit ripening.

Features of seasonal development of black currant (<i> Ribes nigrum</i> L.) in the Arctic zone of the Russian Federation

Black currant is the most valuable berry crop of the Murmansk Province in terms of both biological properties and adaptive qualities necessary for growing in difficult agroclimatic conditions of the North. Every year, a search is carried out for varieties and forms with the best indicators of winter hardiness, yield, disease resistance and environmental friendliness, in order to identify accessions with the most valuable biological and economic traits. The objects of the present study were 24 cultivars of black currant of different ecological and geographical origin obtained in 2015 from the collection of the N. I. Vavilov All-Russian Research Institute of Plant Genetic Resources (VIR). Studies of the black currant collection were carried out in 2017-2021 at the Polar Experiment Station, a branch of VIR. The care of plants was provided according to the agricultural practices developed for growing berry crops in the Polar Region. The results of five-year phenological observations and assessment of winter hardiness in the studied cultivars showed that the onset of vegetation in all accessions occurred annually in the second decade of May, the onset of flowering in the second decade of June, the onset of maturation in the third decade of July, and the growth of shoots ended in the first decade of September. The studied cultivars were combined into groups according to winter hardiness (highly winter-hardy and winter-hardy), as well as the onset of phenophases (early, medium, late), and of ripening dates (early, mid, and late-ripening). Early vegetation was noted in cultivars ‘Pigmei’, ‘Izyumnaya’, ‘Rita’, ‘Volshebnica’, ‘Vasilisa’, ‘Almiai’, ‘Kriviai’, ‘Mila’, ‘Poklon Borisovoi’. Early ripening of the crop was observed in the cultivars ‘Severnoe Siyanie’ (C), ‘Mila’, ‘Izyumnaya’, ‘Rita’, ‘Kriviai’. The late maturing cultivars are ‘Slavyanka’, ‘Kipiana’, ‘Gratsiya’, ‘Chudnoe Mgnovenie’. The most numerous group is that of mid-ripening cultivars (64 %), followed by the group of early maturing (20 %), and late maturing ones (16 %). All the studied cultivars showed high adaptability to the conditions of the Murmansk Province. They had time enough to form the yield, complete the fruiting and growth of shoots before the onset of frosts. Due to the results of five years of research, they can be recommended for cultivation in the Arctic zone of the Russian Federation.

Duration of fungicide spray program for the control of citrus black spot in sweet orange based on cultivar maturation and orchard age

Citrus black spot (CBS) damage and Phyllosticta citricarpa inoculum tend to increase in old orchards and in late-maturing cultivars of sweet orange. However, CBS control in São Paulo citrus belt is based on standard fungicide program of 180–220 days of fruit protection, regardless of cultivar and orchard age. This study aimed to investigate whether the protection period may be adjusted based on the cultivar maturation and age of orchards intended for juice processing. The efficacy of protection periods of 60, 100, 140, 180, 220 and 260 days was determined by assessing CBS incidence and severity and CBS-related fruit drop in 12 orchards over two seasons. The standard protection period, with 180 days targeted for mid-age and 220 days for old orchards, was the most cost effective for mid-season and late-maturing cultivars. These protection periods resulted in a significant reduction in CBS severity and fruit drop by up to ∼95% and ∼50%, respectively. For early-maturing cultivars, the duration of CBS spray program may be drastically reduced to 60 days for mid-age orchards and to 100 days for old orchards. These protection periods significantly reduced CBS severity and fruit drop by up to ∼92% and ∼50%, respectively. These adjustments in CBS fungicide protection period based on cultivar and orchard age may save up to US$14.3 million per season if adopted throughout the main Brazilian citrus belt. The results of this study allow citrus growers to save inputs, reduce costs, improve the operational efficiency within the farm and contribute to a more sustainable citrus industry.

Deciphering the response of thirteen apple cultivars for growth, fruit morphology and fruit physico-chemical attributes during different years

Apple cultivation is one of the most significant means of subsistence in the Kashmir region of the northwestern Himalayas. It is considered as the backbone of the region's economy. Apple cultivation in the region is dominated by a late maturing cultivar “Red Delicious” which usually on maturity causes glut in the market. In order to bring new cultivars in the cultivation, and to expand the maturity season, it is necessary to evaluate the new cultivars on fruit physico-chemical attributes which ultimately decide the market rates before recommending to farmers for cultivars adoption. Therefore, the current study was carried out to evaluate thirteen apple cultivars on physico-chemical attributes over two years, 2017 and 2018 under agro-climatic conditions of Kashmir region The results revealed that cultivars differed significantly in terms of physico-chemical properties. Cultivars with the highest and lowest values for initial fruit set, fruit drop, final fruit retention, and fruit firmness in 2017 did not follow the same trend in 2018. During 2017 and 2018, cultivar Mollie's Delicious possessed the highest fruit length (72.39 mm and 81.45 mm), fruit diameter (81.18 mm and 84.14 mm), and fruit weight (205.85 g and 247.16 g), whereas cultivar Baleman's Cider had the lowest values (50.76 mm and 52.83 mm, 60.10 mm and 62.08 mm, and 71.46 g and 86.94 g), respectively. The harvesting dates were quite spread out during both years of study. Cultivar Mollie's Delicious was harvested the earliest in both years, on August 5th, 2017 and August 8th, 2018. Cultivar Fuji Zehn Aztec was the last cultivar harvested in 2017 on October 2 and in 2018 on October 5. The maximum number of seeds per fruit was noticed in the cultivar Mollie's Delicious (8.34 and 8.71) during both 2017 and 2018, respectively. Cultivar Starkrimson had the fewest seeds per fruit in 2017 (7.11) and 2018 (7.42). Cultivar Baleman's Cider had the highest acidity in 2017 (0.63%) and 2018 (0.52%). In both 2017 (0.25%) and 2018 (0.23%), the Adam's Pearmain cultivar was the least acidic. Cultivar Allington Pippin (16.13 °Brix) and Red Gold (16.73 °Brix) had the highest TSS in 2017 and 2018, respectively, whereas Vance Delicious (12.30 °Brix) and Top Red (10.78 °Brix) had the lowest TSS in 2017 and 2018, respectively. The cultivars Mollie's Delicious and Red Gold had the highest total sugars (11.33 and 11.40%) in 2017 and 2018, respectively. Cultivar Baleman's Cider had the lowest total sugars (9.82%) in 2017 while Top Red (9.78%) in 2018. The cultivar Vance Delicious had the highest ratio of leaves to fruits in 2017 (55.44) and for Shalimar Apple-2 in 2018 (49.65). In 2017, cultivars Fuji Zehn Aztec (29.26) and Silver Spur (24.51), had the fewest leaves per fruit. The highest leaf chlorophyll content was recorded in cultivar Shireen (3.50 and 3.57 mg g−1 fresh weight) during the years 2017 and 2018, respectively. Cultivar Baleman's Cider had the lowest leaf chlorophyll content (2.15 mg g−1 fresh weight) during 2017, while cultivar Allington Pippin (2.09 mg g−1 fresh weight) had the lowest leaf chlorophyll content in 2018. The cultivars Fuji Zehn Aztec, with a yield efficiency of 0.78 kg/cm2 and Silver Spur with a yield efficiency of 1.14 kg/cm2 were the most yield efficient during the years 2017 and 2018, respectively. Cultivar Shalimar Apple-2 was least performing with yield efficiencies of 0.05 and 0.07 kg/cm2 during 2017 and 2018, respectively.The findings suggest that cultivar Mollie's Delicious commercially matures first and has the highest fruit length, diameter, and weight; hence, it can be a good option for cultivation so as to fetch the maximum price in the market when other cultivars are still maturing. Shalimar Apple-2 is precluded for cultivation due to least yield efficiency, whereas cultivars Fuji Zehn Aztec and Silver Spur are recommended to farmers for their higher yield efficiency.

Texture and Key Components of Frozen Cabbage Leaves as Affected by Maturity Type

The objectives of this study were to (i) evaluate the impact of maturity types on the texture and microstructure of frozen cabbage leaves and (ii) elucidate the relationships between variables (alcohol-insoluble solid (AIS), pectin, insoluble dietary fiber (IDF), total soluble solid (TSS), and pH) and the firmness of frozen cabbage leaves. Fourteen cabbage cultivars of four maturity types grown in three regions of Japan for 3 years were used as samples. Higher firmness and less drip loss in frozen cabbage leaves were obtained in the late maturing cultivars, followed by the medium-late, medium, and early maturing cultivars. Scanning electron microscopy showed severe cell wall damage in frozen leaves of the early maturing cabbage, while well-defined individual cells could be observed in the late maturing cabbage. Positive linear correlations between the firmness of frozen cabbage leaves and the amount of cell wall components (AIS (R2 = 0.818), pectin (R2 = 0.670), IDF (R2 = 0.841)) and the concentration of solutes (TSS (R2 = 0.799)) were detected. On the other hand, there was no relationship between pH values and the firmness of frozen cabbage leaves (R2 < 0.1). Thus, we proposed the combination of two phenomena (i.e., greater cell wall rigidity and smaller ice crystals due to the higher solute concentration) regulating the firmness of frozen cabbage leaves. These results highlight the importance of cultivar selection, especially with respect to maturity type, for the manufacture of frozen cut cabbage.

Early–maturing cultivar of winter wheat is more adaptable to elevated [CO2] and rising temperature in the eastern Loess Plateau

Understanding the impacts of rising temperature and elevated [CO2] on different crop cultivars is critical to devising agronomic strategies and cultivar selection in the context of climate change adaptation. The growth period, biomass, and yield of two wheat cultivars (early– vs. late–maturing) were simulated by the Agricultural Production Systems sIMulator (APSIM) validated with pot experiments under the scenarios of elevated [CO2] and 2 °C warming based on the baseline climate for 1961–2016 at Taigu in North China. We also investigated the effects of extreme high temperature on the yield and yield components of these wheat cultivars. We found that APSIM well simulated the changes in the growth period, leaf area index (LAI), biomass, and yield induced by 2 °C warming and elevated [CO2]. Long–term simulations showed that 2 °C warming decreased the growing period between sowing and jointing for both cultivars. 2 °C warming and elevated [CO2] affected the wheat yield mainly by altering the grain numbers. Extreme high temperature decreased the grain numbers and yield of the late–maturing cultivar but not the early–maturing one. The findings suggest that early–maturing cultivar would be better adapted to elevated [CO2] and rising temperature than the late–maturing one in the eastern Loess Plateau.

Multi-Environment Trials and Stability Analysis for Yield-Related Traits of Commercial Rice Cultivars

Multi-environment trials (METs) are essential in plant breeding programs to evaluate crop productivity and adaptability in diverse environments. In this study, we demonstrated the practical use of METs to evaluate grain yield and yield-related traits using 276 Korean rice cultivars, divided into three maturity groups (81 early-, 90 medium-, and 105 medium–late-maturing cultivars) grown in three regions (Jeonju, Suwon, and Miryang) and two planting seasons (early and regular planting) for two years. Due to the narrow genetic variability of the commercial cultivars, which are cultivated in relatively similar environmental conditions, genotype-by-environment interaction (GEI) effects were not statistically significant. However, genotype and environment evaluation using GGE biplot analysis exhibited distinct patterns of mega-environment formation, winning genotypes, ranking genotypes, discriminating power, and representativeness according to the differences in planting seasons and regions. Moreover, the simultaneous selection of stable high-performance genotypes using a weighted average of absolute scores from the singular-value decomposition of the matrix of BLUPs (WAASB) and a multi-trait stability index (MTSI) revealed six recommended genotypes each for early-maturing (Manho, Namil, Unkwang, Odae 1ho, Sinunbong 1ho, and Jonong) and medium-maturing (Sobi, Cheongdam, Shinbaeg, Boramchal, Mimyeon, and Saemimyeon) cultivars, and four genotypes for medium–late-maturing cultivars (Hanmauem, Dami, Baegseolchal, and Hangangchalbyeo). The winning genotypes of each trait can be used as parents to develop regional specialty cultivars by fine-tuning favorable traits, and recommended genotypes can be utilized as elite climate-resilient parents that can aid breeders in improving yield potential and stability across the planting seasons and regions.

Potential for growing ‘Fuji’ apple in Hokkaido under climate change

With its cold climate, Hokkaido grows early- to middle-maturing cultivars of apple. ‘Fuji’, a late-maturing cultivar, is the most popular apple in Japan, but it is not grown in Hokkaido. Warming due to climate change could make Hokkaido suitable for growing ‘Fuji’. We estimated the lower temperature limit for ‘Fuji’ from annual and seasonal （April to October） mean temperatures collected as mesh data in apple orchards in Hirosaki city from 1982 to 1991. The coastal region of western Hokkaido is predicted to become suitable for ‘Fuji’ by about 2050 under the MIROC5 RCP8.5 and RCP2.6 scenarios, and the inland of Hokkaido is predicted to become suitable under RCP8.5. It will be necessary to select appropriate apple cultivars for each cropping region in Hokkaido on the basis of anticipated future Greenhouse Gas emission trends or climate conditions.

Flowering responses of serradella (Ornithopus spp.) and subterranean clover (Trifolium subterraneum L.) to vernalisation and photoperiod and their role in maturity type determination and flowering date stability

Context Serradellas (Ornithopus spp.) are promising alternative annual legumes to subterranean clover (Trifolium subterraneum L.), for permanent, temperate pastures. However, many cultivars exhibit unstable flowering dates across years. This is a risk for seed production and persistence. Aim This study assessed how vernalisation and photoperiod cues determine maturity type and flowering date stability among serradella cultivars. Methods First flower appearance was recorded for early and late maturing cultivars of yellow serradella (Ornithopus compressus L.), French serradella (Ornithopus sativus Brot.) and subterranean clover after exposure to six vernalisation treatments (0, 1, 3, 5, 7 or 9 weeks at 5°C) with subsequent growth under four photoperiods (8, 12, 16 or 20 h). Key results ‘Intrinsic earliness’ differed by only zero to three nodes for cultivars within species, indicating that maturity type was determined primarily by a cultivar’s responses to vernalisation and photoperiod. An interaction between these responses was observed, with a precipitous decline in the requirement for vernalisation when photoperiods exceeded 12 h. Many cultivars also displayed a persistent component to their vernalisation response, whereby long photoperiods (20 h) did not completely negate the response to vernalisation. Conclusions Later maturity was associated particularly with need for long exposure to the vernalisation treatment to minimise the duration from sowing to first flower appearance. Stable flowering is more likely when a cultivar has components of its vernalisation requirement that are not satisfied before autumn ends to prevent premature flowering, and a photoperiod response in spring that overrides any unmet vernalisation requirement. Implications Persistence by serradella cultivars requires selection for suitable responsiveness to vernalisation and photoperiod.

Can the cropping systems of the Nile basin be adapted to climate change?

Climate change poses a fundamental threat to agriculture within the Nile basin due to the magnitude of projected impacts and low adaptive capacity. So far, climate change impacts on agriculture for the basin have mostly been assessed for single-cropping systems, which may bias the results considering that the basin is dominated by different cropping systems, with about one-third of the crop area under double cropping. In this study, we simulate single- and double-cropping systems in the Nile basin and assess the climate change impacts on different cropping systems under two scenarios, i.e. “no adaptation” and “adaptation to a late-maturing cultivar”. We find that the mean crop yields of maize, soybean and wheat decrease with future warming without cultivar adaptation. We attribute this to the shortening of the growing season due to increased temperature. The decrease is stronger in all single-cropping systems (12.6–45.5%) than in double-cropping systems (5.9–26.6%). The relative magnitude of yield reduction varies spatially with the greatest reduction in the northern part of the basin experiencing the strongest warming. In a scenario with cultivar adaptation, mean crop yields show a stronger increase in double-cropping systems (14.4–35.2%) than single-cropping systems (8.3–13.7%). In this scenario, farmers could possibly benefit from increasing cropping intensities while adapting to late-maturing cultivars. This study underscores the importance of accounting for multiple-cropping systems in agricultural assessments under climate change within the Nile basin.

Phenotypic diversity and stability of early maturing Barnyard Millet (Echinochloa sp.) germplasm for grain yield and its contributing traits

Barnyard millet is one of the oldest domesticated millets in the semi-arid tropics of Asia and Africa. Developing early maturing cultivars is one of the important breeding goals in barnyard millet, which can fit well when main crops fail, or during the late onset of monsoon. Thus, this study was carried out to test the phenotypic diversity, character association and path coefficients, and stability of early maturing barnyard millet accessions. The MDU 1, a slightly late-maturing (95 days) cultivar, was used to identify early maturing accessions than the control with a considerably higher yield. Diversity as revealed by D2 analysis indicated that the trait grain yield had contributed the most towards the diversity followed by the traits such as thousand-grain weight and fodder yield per plant. The accessions IEc 350 and IEc 356 showed the highest fodder yield and grain yield per plant, and higher per day productivity than the control, MDU 1. Genotypic correlations revealed a significantly positive correlation of the grain yield with most traits investigated including days to maturity and fodder yield, and the trait fodder yield per plant showed a highly positive indirect effect on grain yield. Hence, these traits could be considered during the selection process for improving grain yield. Stability analysis identified two accessions, IEc 350 and IEc 356, and the MDU 1, as the stable high-yielding accessions. Hence, these high-yielding stable accessions can efficiently be used in barnyard millet improvement for developing early maturing varieties.

Mineral composition of repair raspberry (Rubus idaeus L.) fruits.

In recent years, raspberry breeding has shifted its emphasis from agronomic performance to characteristics related to the sensory qualities of the fruit and its potential health benef its. The therapeutic and preventive properties of raspberries are related to their biochemical composition. In this regard, the purpose of the work was to determine the content of macro- and micronutrients in fruits of different cultivars of repair raspberry using modern high-tech analytical methods and the selection of genetic sources of the analyzed elements for further breeding. The objects of the research were 17 cultivars of repair raspberry of different ecological and geographical origin from the genetic plant bioresource collection of FSBSO ARHCBAN. It was found that the ash residue of berries contains 12 major elements, which form the following descending series: K > P > Mg ≥ Mo > Ca > S ≥ Ni > Zn > Mn > Se > Fe ≥ Co. The largest proportion of ash residue in raspberry fruits is K. Depending on the cultivar, its quantity averaged from 12.81 wt % (Samorodok and Karamelka) to 22.37 wt % (Atlant). The minimum K content was observed in the ash of the Carolina cultivar (5.62 wt %), while in berries of this cultivar Mg (2.91), Ca (2.62) and Zn (0.14 wt %) accumulated above average. Among the group of early maturing cultivars, the cultivar Yubileinaya Kulikova stands out with a high content of Mo (4.63), Ca (2.19), Fe (0.25) and Co (0.21 wt %). The cultivar Pingvin is characterized by a high content of K (22.65) and Se (0.31 wt %). The medium maturity cultivar Samorodok is characterized by a higher content of P (4.08), S (0.47), Ni (0.51) and Zn (0.26 wt %). Among the late maturing cultivars, the cultivar Poranna Rosa stands out with the preferential accumulation of nine elements: Mg (2.98), P (4.42), S (0.36), K (20.34), Ca (1.71), Mn (0.14), Co (0.13), Se (0.21) and Mo (3.08 wt %). Correlation relationships between the elements have been established. Samples with the highest accumulation of macro- and microelements in berries represent genetic sources for further selection of raspberry for improvement of the mineral composition of fruits.

Nitrogen fertilization can mitigate cotton yield loss by temporary shading at early flowering

Cotton (Gossypium hirsutum L.) yield is decreased under low radiation, but there are few reports on possible interactions of N fertilizer application and light limitation on cotton production. The objective of this work was to evaluate growth, yield components, and boll distribution in cotton as affected by N rates under light restriction. Three experiments were conducted for two years in Central (Primavera do Leste and Chapadão do Sul) and Southeastern (Itapeva) Brazil. Cotton plants were shaded at early flowering to a 42 % reduction in global radiation for 16–25 days. Four N rates were used in Primavera do Leste and Itapeva; and three N rates and two genotypes, an early- (FM 906GLT) and a late-maturing (FM 983GLT) cultivar, were used in Chapadão do Sul. Shading decreased lint yield by 10 % in Primavera do Leste and by 12 % in Chapadão due to 24 % and 32 % reduction in boll number at the lower third of the plant, respectively. In Itapeva, the number of bolls at the lower fruiting branches was decreased 19% by shading, but a 10% lint yield reduction was observed only with 35 kg ha−1 of N. As to the main effects, lint yield and number of bolls increased with N rates up to 155, 142 and 105 kg ha−1, depending on the site. Lint yield of shaded plants was more responsive to higher N rates, which also increased plant height, number of bolls and the main stem node number of the last fruiting branch. Cotton cultivars had similar lint yields despite differences in boll distribution. At lower fruiting branches, the early-maturing cultivar showed an average boll number 59 % higher, but the late one produced 81 % and 63 % more bolls on the upper branches at 105 and 185 kg ha−1 of N, respectively. We concluded that N-deficiency inhibited the recovery of cotton from losses caused by shading, whereas a high-N availability minimizes damages after shading during blooming.

Effect of Drought Stress on Potato Production: A Review

Potato is the third most consumed crop globally after rice and wheat. It is a short-duration crop, versatile in use, suitable for growing in a wide range of environments, and its production is increasing rapidly. The modern potato is considered a drought-sensitive crop, and it is susceptible to yield loss because of drought stress. Unfortunately, drought severity, frequency, and extent have been increasing around the globe because of climate change. Potato drought susceptibility has primarily been attributed to its shallow root system. However, several studies in past decades have suggested that drought susceptibility of potato also depends upon the type, developmental stage, and the morphology of the genotype, and the duration and severity of drought stress. They have been overlooked, and root depth is considered the only significant cause of potato drought susceptibility. This review combines these studies to understand the varying response of potato genotypes. This review also explores the current potato production scenario and the effect of varying degrees of drought stress on potatoes’ growth, development, and yield. In the absence of drought-tolerant genotypes, agronomic practices should be improved to mitigate drought stress. Late maturing cultivars, nutrient management, mulching, and foliar application of plant growth regulators can be used during prolonged droughts. Irrigation at tuber initiation and the tuber bulking stage during early droughts can reduce the adverse effects of drought.

Optimizing sowing window, cultivar choice, and plant density to boost maize yield under RCP8.5 climate scenario of CMIP5.

The impacts of climate change and possible adaptations to food security are a global concern and need greater focus in arid and semi-arid regions. It includes scenario of Coupled Model Intercomparison Phase 5 (CMIP-RCP8.5). For this purpose, two DSSAT maize models (CSM-CERES and CSM-IXIM) were calibrated and tested with two different maize cultivars namely Single Cross 10 (SC10) and Three Way Cross 324 (TW24) using a dataset of three growing seasons in Nile Delta. SC10 is a long-growing cultivar that is resistant to abiotic stresses, whereas TW24 is short and sensitive to such harsh conditions. The calibrated models were then employed to predict maize yield in baseline (1981-2010) and under future time slices (2030s, 2050s, and 2080s) using three Global Climate Models (GCMs) under CMIP5-RCP8.5 scenario. In addition, the use of various adaptation options as shifting planting date, increasing sowing density, and genotypes was included in crop models. Simulation analysis showed that, averaged over three GCMs and two crop models, the yield of late maturity cultivar (SC10) decreased by 4.1, 17.2, and 55.9% for the three time slices of 2030s, 2050s, and 2080s, respectively, compared to baseline yield (1981-2010). Such reduction increased with early maturity cultivar (TW24), recording 12.4, 40.6, and 71.3% for near (2030s), mid (2050s), and late century (2080s) respectively relative to baseline yield. The most suitable adaptation options included choosing a stress-resistant genotype, changing the planting date to plus or minus 30days from baseline planting date, and raising the sowing density to 9m-2 plants. These insights could minimize the potential reduction of climate change-induced yields by 39% by late century.

Diverging water-saving potential across China's potato planting regions

China ranks the first in total planting area and production of potato (Solanum tuberosum L.) over the world. However, high potato yield depends on a large amount of irrigation that raises a series of environment problems. Assessing the water-saving potential across China’s potato planting regions is of importance for maintaining sustainable development of potato production. In this study, we firstly evaluated the potential yields, rainfed yields, and their gaps of potato across different potato planting regions, and then presented optimal agronomic management options (planting date, cultivar maturity, and irrigation schedule) by considering both yield and water use efficiency of potato under the limitation of available water resources with validated APSIM-Potato model. Along the distribution of growth period solar radiation, potential yield of potato was highest in the North Single planting region (NS), followed by the Central Double planting region (CD), Southwest Mixed planting region (SWM), and South Winter planting region (SW). However, rainfed yield of potato was highest in CD followed by NS, SW, and SWM along the distribution of the reproductive growth period precipitation. Under the limitation of available water resources, most potato planting regions should select middle−late maturing cultivars while optimal planting dates varied among regions with earlier planting in north China and later planting in south China compared with normal planting date. Based on the optimization of planting date, cultivar maturity, and irrigation schedule, there is a large water-saving potential in China’s potato planting regions. Average irrigation amount could be decreased by 66% in SW, 49% in SWM, 40% in NS, and 29% in CD, respectively, relative to irrigation quota. Our study suggests that optimizing planting date, cultivar maturity, and irrigation management could realize win-win of yield and water use efficiency and provide a scientific support for water-saving irrigation of potato production in China.

Two divergent haplotypes from a highly heterozygous lychee genome suggest independent domestication events for early and late-maturing cultivars

Lychee is an exotic tropical fruit with a distinct flavor. The genome of cultivar ‘Feizixiao’ was assembled into 15 pseudochromosomes, totaling ~470 Mb. High heterozygosity (2.27%) resulted in two complete haplotypic assemblies. A total of 13,517 allelic genes (42.4%) were differentially expressed in diverse tissues. Analyses of 72 resequenced lychee accessions revealed two independent domestication events. The extremely early maturing cultivars preferentially aligned to one haplotype were domesticated from a wild population in Yunnan, whereas the late-maturing cultivars that mapped mostly to the second haplotype were domesticated independently from a wild population in Hainan. Early maturing cultivars were probably developed in Guangdong via hybridization between extremely early maturing cultivar and late-maturing cultivar individuals. Variable deletions of a 3.7 kb region encompassed by a pair of CONSTANS-like genes probably regulate fruit maturation differences among lychee cultivars. These genomic resources provide insights into the natural history of lychee domestication and will accelerate the improvement of lychee and related crops.

‘BRS F183’ (Potira): Cultivar de batata de duplo propósito, com alto potencial produtivo e excelente qualidade de fritura de palitos

ABSTRACT ‘BRS F183’ (Potira) is a late-maturing and red skin potato cultivar, suitable for French fry processing, due to tuber high dry matter content of long oval shape, large size, light yellow flesh, and light fry color. It is also suitable for the fresh market due to its attractive tubers of intense red color, smooth skin and shallow eyes. In six trials, ‘BRS F183’ showed average tuber yields that did not differ from ‘Asterix’. The marketable yield was relatively high, reaching 98.5% in the tropical ecosystem. Larger tubers of ‘BRS F183’ than ‘Asterix’ were also observed in the autumn crop of the subtropical ecosystem. In most of the trials, the dry matter content was higher than that of ‘Asterix’, varying from 20.5 to 23.0%. A very low incidence of tuber disorders was observed in ‘BRS F183’, with the secondary growth lower than ‘Asterix’. ‘BRS F183’ presented medium tuber dormancy. Tuber glucose content suitable for French fry processing (≤1.2 mg g-1 of fresh mass) was shown by ‘BRS F183’ after harvest and storage at 7.5°C, 8.9°C and 20°C for up to 180 days, while ‘Asterix’ was suitable up to 120 days after storage at 8.9ºC. ‘BRS F183’ is moderately resistant to early blight and moderately susceptible to late blight. It is susceptible to PVY, PLRV, and root-knot nematode. Field observations indicate that resistance/susceptibility to soft rot, black scurf, and bacterial wilt of ‘BRS F183’ is not different from the main cultivars grown in the country. However, higher susceptibility to common scab was shown in some validation tests. ‘BRS F183’ was released in 2020 by Embrapa, as a product of the breeding program developed by Embrapa Temperate Agriculture and Embrapa Vegetables.