scholarly journals Calcium Sprays and Timing Affect Fruit Calcium Concentrations, Yield, Fruit Weight, and Cork Spot of `Anjou' Pears

HortScience ◽  
1995 ◽  
Vol 30 (5) ◽  
pp. 1037-1039 ◽  
Author(s):  
J.T. Raese ◽  
S.R. Drake

Calcium sprays (CaCl2, Mora-Leaf-Ca + Link Ca, or Stopit) increased fruit Ca concentrations and reduced the incidence of cork spot of `Anjou' pears (Pyrus communis L.) during four seasons. All Ca sprays increased yield relative to the control. All sprays resulted in some injury to leaves and fruit, but fruit was acceptable for marketing. At the low rate, Stopit sprays were the least injurious. Early season sprays, in June to July, produced less leaf and fruit injury than late-season sprays, in July to August, or early + late-season sprays. Early or late-season Ca sprays resulted in slightly larger fruit than early + late sprays. Either late or early + late-season sprays led to higher Ca concentrations in fruit cortex than early sprays.

2008 ◽  
Vol 56 (2) ◽  
pp. 213-221 ◽  
Author(s):  
O. Kehinde ◽  
E. Idehen

Genetic variability and correlation analysis were studied in 20 accessions of ‘egusi’ melon during two growing seasons. The genotypic correlation coefficients with seed yield were partitioned into direct and indirect effect causes. Heritability in the broad sense ranged from 17% for fruit circumference to 90% for days to germination and flowering in the early season, while in the late season, heritability ranged from 7% for seed weight per fruit to 88% for days to germination. High phenotypic and genotypic coefficients of variation were recorded for seed yield while days to maturity had the lowest in both seasons. Fruit circumference and fruit weight had significant genotypic and phenotypic correlation with seed yield in the early season, while number of branches per plant, vine length per plant, number of fruits per plant and fruit circumference per plant showed significant genotypic and phenotypic correlation with seed yield in the late season. Environmental correlation coefficients were significant between seed yield and vine length per plant, number of fruits per plant and fruit size per plant. Vine length per plant and fruit circumference per plant had the largest positive direct effect on seed yield. Knowledge of the relationship of these characters with seed yield will aid in the selection of genotypes that have high seed yield, which will also be specific to the two major seasons in the year.


2013 ◽  
Vol 58 (3) ◽  
pp. 167-176
Author(s):  
Dragan Milatovic ◽  
Dejan Djurovic ◽  
Gordan Zec

This study was aimed at evaluating of 14 new apricot cultivars created at the Faculty of Horticulture in Lednice in the Czech Republic in order to recommend the best of them for growing in the Belgrade region. The study was carried out at the Experimental station ?Radmilovac? of the Faculty of Agriculture in Belgrade over a period of five years (2009-2013). The experimental orchard was established in 2007, the rootstock was Myrobalan seedling, and tree spacing was 4.5 x 3 m. The control cultivar for comparison was the clone of ?Velkopavlovick?? cultivar (type of ?Hungarian Best?), LE-12/2. Flowering of introduced cultivars started from three days before to one day after the control cultivar, while the maturation time ranged from 19 days earlier in cultivar ?Leskora? to 12 days after the control in cultivar ?Sophia? (LE-2926). Compared with the control cultivar, significantly higher yield was achieved only in cultivar ?Palava?, while significantly higher fruit weight was recorded in three cultivars: ?Candela? (LE-2927), ?Sophia? (LE-2926) and ?Betinka? (LE-3276). Cultivars ?Sophia? and ?Betinka? got the best scores for fruit appearance, while cultivars ?Marlen? and ?Lebona? ranked the highest for fruit taste. Among studied apricot cultivars, for the cultivation in the Belgrade region, the following cultivars can be recommended as promising: ?Palava? (early season), ?Betinka? (mid-season) and ?Sophia? (late season). Regarding the large size and attractive appearance of fruits, these cultivars are more suitable for fresh consumption, but they can also be used for processing.


2016 ◽  
Vol 8 (1) ◽  
pp. 85-92
Author(s):  
Chikezie O. ENE ◽  
Peter E. OGBONNA ◽  
Christian U. AGBO ◽  
Uche P. CHUKWUDI

Sixteen exotic and indigenous cucumber genotypes (Cucumis sativus L.) were evaluated under early and late seasons planting. This was to characterize the cucumber genotypes based on their performance in the derived savannah of Southeast Nigeria agro-ecological zone and estimate character association and contribution towards total fruit yield per hectare. The vegetative traits, such as vine length, number of branches, number of leaves and leaf area were measured at 8 weeks after planting. The phonological traits measured were: days to flower initiation and days to 50% flowering. The reproductive traits like number of staminate flowers per plant, number of pistillate flowers per plant, fruit length, fruit girth, fruit weight per plant, number of fruits per plant, average fruit weight and total fruit yield per hectare were also recorded. Obtained data was subjected to analysis of variance in randomized complete block design and path analysis. The results showed a highly significant difference (p<0.01) among the genotypes in all the traits studied in both seasons. ‘Beit Alpha’ genotype gave the highest fruit yield/ha in early season planting, while in the late season, the highest yield producer was ‘Ashely’. In both seasons, vine length, number of branches and leaves, leaf area, number of pistillate and staminate flowers/plant, number of fruit and fruit weight/plant showed positive and significant correlation with total fruit yield/ha. In both seasons, the highest positive direct effect on yield was recorded in fruit weight/plant. Significantly (p<0.05), the highest total fruit yield/ha was recorded in the early rainy season planting in this agro ecological zone. Based on high fruit yield, ‘Beit Alpha’ genotype for early season planting and ‘Ashley’ genotype for late season are recommended for cultivation in the Derived Savannah, Southeast Nigeria agro ecological zone. 


1990 ◽  
Vol 70 (2) ◽  
pp. 157-167 ◽  
Author(s):  
M. A. NAETH ◽  
D. J. PLUTH ◽  
D. S. CHANASYK ◽  
A. W. BAILEY ◽  
A. W. FEDKENHEUER

The impacts of long-term grazing on compaction were assessed in mixed prairie and fescue grassland ecosystems of Alberta. Grazing regimes were of light to very heavy intensities, grazed early, late, and continuously during the growing season. Bulk density was measured with a surface moisture/density gauge and a combination moisture/density probe to 65 cm. Penetration resistance to 30 cm was measured with a cone penetrometer. Solonetzic soils were less sensitive to compaction under grazing than Chernozemic soils. Heavy intensity and/or early season grazing had greater impacts on compaction than light intensity and/or late season grazing. Under the former grazing regimes, bulk density increased to 7.5 cm at Kinsella and 65 cm at Stavely; penetration resistance increased to depths of 2.5 cm at Brooks, 15 cm at Kinsella, and 30 cm at Stavely. Heavy trampling versus regular grazing increased penetration resistance to depths of 30 and 10 cm under heavy intensity and/or early season and light intensity and/or late season grazing, respectively. Late season grazing at Brooks and light to moderate grazing at Stavely may be used as management models to reduce compaction under grazing. Trends were not as clear at Kinsella, but light June and autumn grazing had the least compacting effect. Key words: Compaction, grazing, rangelands, penetration resistance, bulk density


2010 ◽  
Vol 18 (3) ◽  
pp. 606-610 ◽  
Author(s):  
Wu LI ◽  
Xiao-Juan YANG ◽  
Xiang-Ru TANG ◽  
Guo-Xi LI ◽  
Guo-Wei PENG ◽  
...  

2021 ◽  
Vol 12 (4) ◽  
pp. 1371-1391
Author(s):  
Raed Hamed ◽  
Anne F. Van Loon ◽  
Jeroen Aerts ◽  
Dim Coumou

Abstract. The US agriculture system supplies more than one-third of globally traded soybean, and with 90 % of US soybean produced under rainfed agriculture, soybean trade is particularly sensitive to weather and climate variability. Average growing season climate conditions can explain about one-third of US soybean yield variability. Additionally, crops can be sensitive to specific short-term weather extremes, occurring in isolation or compounding at key moments throughout crop development. Here, we identify the dominant within-season climate drivers that can explain soybean yield variability in the US, and we explore the synergistic effects between drivers that can lead to severe impacts. The study combines weather data from reanalysis and satellite-informed root zone soil moisture fields with subnational crop yields using statistical methods that account for interaction effects. On average, our models can explain about two-thirds of the year-to-year yield variability (70 % for all years and 60 % for out-of-sample predictions). The largest negative influence on soybean yields is driven by high temperature and low soil moisture during the summer crop reproductive period. Moreover, due to synergistic effects, heat is considerably more damaging to soybean crops during dry conditions and is less problematic during wet conditions. Compounding and interacting hot and dry (hot–dry) summer conditions (defined by the 95th and 5th percentiles of temperature and soil moisture respectively) reduce yields by 2 standard deviations. This sensitivity is 4 and 3 times larger than the sensitivity to hot or dry conditions alone respectively. Other relevant drivers of negative yield responses are lower temperatures early and late in the season, excessive precipitation in the early season, and dry conditions in the late season. We note that the sensitivity to the identified drivers varies across the spatial domain. Higher latitudes, and thus colder regions, are positively affected by high temperatures during the summer period. On the other hand, warmer southeastern regions are positively affected by low temperatures during the late season. Historic trends in identified drivers indicate that US soybean production has generally benefited from recent shifts in weather except for increasing rainfall in the early season. Overall, warming conditions have reduced the risk of frost in the early and late seasons and have potentially allowed for earlier sowing dates. More importantly, summers have been getting cooler and wetter over the eastern US. Nevertheless, despite these positive changes, we show that the frequency of compound hot–dry summer events has remained unchanged over the 1946–2016 period. In the longer term, climate models project substantially warmer summers for the continental US, although uncertainty remains as to whether this will be accompanied by drier conditions. This highlights a critical element to explore in future studies focused on US agricultural production risk under climate change.


2019 ◽  
Vol 56 (2) ◽  
pp. 218-226
Author(s):  
Jiana Chen ◽  
Min Huang ◽  
Fangbo Cao ◽  
Xiaohong Yin ◽  
Yingbin Zou

AbstractHigh-yielding short-duration cultivars are required due to the development of mechanized large-scale double-season rice (i.e. early- and late-season rice) production in China. The objective of this study was to identify whether existing early-season rice cultivars can be used as resources to select high-yielding, short-duration (less than 115 days) cultivars of machine-transplanted late-season rice. Field experiments were conducted in Yongan, Hunan Province, China in the early and late rice-growing seasons in 2015 and 2016. Eight early-season rice cultivars (Liangyou 6, Lingliangyou 211, Lingliangyou 268, Xiangzaoxian 32, Xiangzaoxian 42, Zhongjiazao 17, Zhongzao 39, and Zhuliangyou 819) with growth durations of less than 115 days were used in 2015, and four cultivars (Lingliangyou 268, Zhongjiazao 17, Zhongzao 39, and Zhuliangyou 819) with good yield performance in the late season in 2015 were grown in 2016. All cultivars had a growth duration of less than 110 days when grown in the late season in both years. Zhongjiazao 17 produced the maximum grain yield of 9.61 Mg ha−1 with a daily grain yield of 108 kg ha−1 d−1 in the late season in 2015. Averaged across both years, Lingliangyou 268 had the highest grain yield of 8.57 Mg ha−1 with a daily grain yield of 95 kg ha−1 d−1 in the late season. The good yield performance of the early-season rice cultivars grown in the late season was mainly attributable to higher apparent radiation use efficiency. Growth duration and grain yield of early-season rice cultivars grown in the late season were not significantly related to those grown in the early season. Our study suggests that it is feasible to select high-yielding short-duration cultivars from existing early-season rice cultivars for machine-transplanted late-season rice production. Special tests by growing alternative early-season rice cultivars in the late season should be done to determine their growth duration and grain yield for such selection.


2018 ◽  
Vol 10 (4) ◽  
pp. 567-574
Author(s):  
Charles U. UBA ◽  
Christian U. AGBO ◽  
Uchechukwu P. CHUKWUDI ◽  
Andrew A. EFUSIE ◽  
Stella O. MUOJIAMA

The understanding of yield and the interaction with its components is very important for selection in early generations of crop breeding. Twelve maize genotypes were collected from International Institute for Tropical Agriculture (IITA) along with seven landraces in order to identify the contribution of different traits to yield improvement. The experiments were carried out in two different seasons (March/April-early and July/August- late) in a randomized complete block design with three replications. Early season planting had a higher grain yield than late season planting. The difference in grain yield between early and late season was 3.92 tons/ha. This represents a 27.8% increase in grain yield during the early season over the late season planting. Number of ears per plant and shelling percentage were not influenced by seasonal effects. Ear weight and days to tasselling showed the highest direct positive effects of 0.972 and 0.665, respectively on grain yield, during early season. Furthermore, ear weight, followed by shelling percentage, exerted the highest direct positive effect on grain yield in late season. Higher indirect positive effects were obtained for ear diameter, ear length, ear height and plant height via ear weight in both seasons. Ear weight, days to tasselling and ear length were identified as the major traits affecting yield of maize in both seasons in the derived Savannah agro-ecology.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
W. James Grichar ◽  
Jack J. Rose ◽  
Peter A. Dotray ◽  
Todd A. Baughman ◽  
D. Ray Langham ◽  
...  

Growth chamber experiments were conducted to evaluate the response of sesame to PRE and POST applications of soil residual herbicides. PRE applications of acetochlor andS-metolachlor at 1.26 and 1.43 kg ai·ha−1showed little or no sesame injury (0 to 1%) 4 wks after herbicide treatments (WAT). POST treatments of acetochlor and trifluralin made 3 wks after planting (WAP) resulted in greater sesame injury (40%) compared to applications at bloom (18%). Field studies were conducted in Texas and Oklahoma during the 2014 and 2015 growing seasons to determine sesame response to clethodim, diuron, fluometuron, ethalfluralin, quizalofop-P, pendimethalin, pyroxasulfone, trifluralin, and trifloxysulfuron-sodium applied 2, 3, or 4 weeks after planting (WAP). Late-season sesame injury with the dinitroaniline herbicides consisted of a proliferation of primary branching at the upper nodes of the sesame plant (in the shape/form of a broom). Ethalfluralin and trifluralin caused more “brooming” effect than pendimethalin. Some yield reductions were noted with the dinitroaniline herbicides. Trifloxysulfuron-sodium caused the greatest injury (up to 97%) and resulted in yield reductions from the untreated check. Early-season diuron injury (leaf chlorosis and necrosis) decreased as application timing was delayed, and late-season injury was virtually nonexistent with only slight chlorosis (<4%) still apparent on the lower leaves. Sesame yield was not consistently affected by the diuron treatments. Fluometuron caused early-season injury (stunting/chlorosis), and a reduction of yield was observed at one location. Pyroxasulfone applied 2 WAP caused up to 25% sesame injury (stunting) but did not result in a yield reduction. Quizalofop-P caused slight injury (<5%) and no reduction in yield.


2006 ◽  
Vol 15 (1) ◽  
pp. 37 ◽  
Author(s):  
Eric E. Knapp ◽  
Jon E. Keeley

Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within replicated early and late season burn units. Two indices of fire severity were evaluated in the same plots after the burns. Scorch height ranged from 2.8 to 25.4 m in early season plots and 3.1 to 38.5 m in late season plots, whereas percentage of ground surface burned ranged from 24 to 96% in early season plots and from 47 to 100% in late season plots. Scorch height was greatest in areas with steeper slopes, higher basal area of live trees, high percentage of basal area composed of pine, and more small woody fuel. Percentage of area burned was greatest in areas with less bare ground and rock cover (more fuel continuity), steeper slopes, and units burned in the fall (lower fuel moisture). Thus topographic and biotic factors still contribute to the abundant heterogeneity in fire severity with prescribed burning, even under the current high fuel loading conditions. Burning areas with high fuel loads in early season when fuels are moister may lead to patterns of heterogeneity in fire effects that more closely approximate the expected patchiness of historical fires.


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