scholarly journals Performance of 19 Pecan Cultivars and Selections in Southern Georgia

2014 ◽  
Vol 24 (3) ◽  
pp. 407-412
Author(s):  
Patrick J. Conner
Keyword(s):  
Scab Resistance ◽  
Development Programs ◽  
Alternate Bearing ◽  
Department Of Agriculture ◽  
Breeding Programs ◽  
Cultivar Development ◽  
Kernel Quality ◽  
Pecan Scab ◽  
Nut Production ◽  
Southern Georgia

Nineteen pecan (Carya illinoinensis) clones were evaluated over a period of 18 years in a test orchard located in southern Georgia. Clones tested were primarily U.S. Department of Agriculture selections, but two grower-discovered cultivars, Jubilee and Surprize, were also trialed. Annual yields were measured for each tree in the test throughout the test period and the alternate bearing intensity of each cultivar was calculated. Average annual in-shell nut production in years 1–10 ranged from 12 lb in the precocious USDA 76-4-41 to 0 lb in the non-precocious USDA 72-8-4. Wide variation was seen in nut production of trees in years 11–18, averaging from 10 to 60 lb nut yield per year. A subsample of nuts was taken from each tree annually and percent kernel, nuts per pound, specific gravity, and nut volume were determined. Significant differences were found between clones for each of these traits. Differences were also found for the presence of damage from pecan scab [Fusicladium effusum (synonym Cladosporium caryigenum)] and black pecan aphid (Melanocallis caryaefoliae). Most clones were not acceptable for use in Georgia due to small nut size or poor kernel quality, but two clones merit further testing in this region. USDA 70-3-34 produced a large nut with good quality and scab resistance, but needs to be evaluated with mechanical crop thinning to improve kernel quality in high crop-set years. USDA 74-1-12 produced good yields of excellent quality, medium-sized pecans and should be trialed with greater tree numbers. Several other clones were found to have traits of interest to pecan breeding programs including: pecan scab resistance, large nut size, and high kernel percentage. Results of this trial suggest that cultivar development programs in Georgia should place greater selection emphasis on large nut size.

scholarly journals Performance of 15 Pecan Cultivars and Selections over 20 Years in Southern Georgia

2002 ◽  
Vol 12 (2) ◽  
pp. 274-281
Author(s):  
Patrick J. Conner ◽  
Ray E. Worley
Keyword(s):  
Carya Illinoinensis ◽  
Harvest Date ◽  
Average Yield ◽  
Alternate Bearing ◽  
Commercial Use ◽  
Kernel Quality ◽  
Nut Production ◽  
Southern Georgia ◽  
Early Harvest ◽  
Calculated Average

Fifteen pecan (Carya illinoinensis) genotypes were evaluated over a period of 20 years in a test orchard located near Tifton, Ga. Genotypes tested included seedling selections (`Candy', `Maramec', `Melrose', `Moreland', `Sumner', and `Western Schley'), USDA releases (`Creek', `Kanza', `Kiowa', and `Pawnee'), and USDA selections (USDA 41-19-20, USDA 53-11-139, USDA 53-9-1, USDA 57-7-22, and USDA 64-11-17). Actual yields were measured for each tree in the test throughout the test period and the alternate bearing intensity (I) of each cultivar was calculated. Average annual nut production in years 1 to 10 ranged from 19 lb (8.6 kg) in the precocious cultivar `Candy' to 6 lb (2.7 kg) in the nonprecocious cultivar `Melrose'. Although a wide variation was seen in the average yield of clones in years 11 to 20, differences were not significant. A subsample of nuts was taken for each tree annually and percent kernel, nuts/lb, specific gravity, and nut volume were determined. Significant differences were found between clones for each of these traits. Most clones were not acceptable for commercial use in Georgia due to small nut size, poor kernel quality, or excessive alternate bearing. Recommended clones include: `Pawnee', which produced large nuts of excellent quality with an early harvest date, `Sumner', which produced large nuts of moderate quality with a late harvest date, and `Kiowa', a precocious bearer of large, good-quality nuts.

scholarly journals Plant breeding in the semiarid region of Brazil: examples of success

2012 ◽  
Vol 12 (spe) ◽  
pp. 57-66 ◽  
Author(s):  
Manoel Abílio de Queiroz ◽  
Levi de Moura Barros ◽  
Luiz Paulo de Carvalho ◽  
Jonas de Araújo Candeia ◽  
Edinardo Ferraz
Keyword(s):  
Cotton Fiber ◽  
Production Systems ◽  
Rio Grande ◽  
Semiarid Region ◽  
Breeding Programs ◽  
Caatinga Biome ◽  
Colored Cotton ◽  
Nut Production ◽  
Production Area ◽  
Naturally Colored Cotton

The Northeastern region of Brazil comprises the Caatinga biome (900,000 km²) part of which is a semiarid region with rainfed and irrigated production systems. Among the successful breeding programs are cashew and cotton. The first led to a substantial increase in nut production in Ceará, Rio Grande do Norte and Piauí and the second bred a naturally colored cotton fiber, now processed in small clothing industries in Paraiba, exporting to 11 countries. In the lower-middle São Francisco valley, the previously grown onion was replaced by improved varieties, on 90% of the production area, and by industrial tomato, introduced by research in 1972, which came to be used on more than 80% of the area at the time. The participation of the private sector and continuity of breeding programs were crucial for the success. More examples of success are expected with the establishment of postgraduate courses in Agricultural Sciences in the Semiarid region.

Identification of Resistance to Powdery Mildew in Publicly Available Male Hop Germplasm

2018 ◽  
Vol 19 (3) ◽  
pp. 258-264
Author(s):  
David H. Gent ◽  
Briana J. Claassen ◽  
Megan C. Twomey ◽  
Sierra N. Wolfenbarger
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Pacific Northwest ◽  
Western United States ◽  
R Genes ◽  
Sources Of Resistance ◽  
Department Of Agriculture ◽  
Breeding Programs ◽  
The Pacific ◽  
The U.S

Powdery mildew (caused by Podosphaera macularis) is one of the most important diseases of hop in the western United States. Strains of the fungus virulent on cultivars possessing the resistance factor termed R6 and the cultivar Cascade have become widespread in the Pacific Northwestern United States, the primary hop producing region in the country, rendering most cultivars grown susceptible to the disease at some level. In an effort to identify potential sources of resistance in extant germplasm, 136 male accessions of hop contained in the U.S. Department of Agriculture collection were screened under controlled conditions. Iterative inoculations with three isolates of P. macularis with varying race identified 23 (16.9%) accessions with apparent resistance to all known races of the pathogen present in the Pacific Northwest. Of the 23 accessions, 12 were resistant when inoculated with three additional isolates obtained from Europe that possess novel virulences. The nature of resistance in these individuals is unclear but does not appear to be based on known R genes. Identification of possible novel sources of resistance to powdery mildew will be useful to hop breeding programs in the western United States and elsewhere.

scholarly journals Quantitative Trait Loci (QTL) Analysis Reveals Both Broad-Spectrum and Isolate-Specific QTL for Scab Resistance in an Apple Progeny Challenged with Eight Isolates of Venturia inaequalis

2004 ◽  
Vol 94 (4) ◽  
pp. 370-379 ◽  
Author(s):  
F. Calenge ◽  
A. Faure ◽  
M. Goerre ◽  
C. Gebhardt ◽  
W. E. Van de Weg ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Quantitative Trait ◽  
Venturia Inaequalis ◽  
Scab Resistance ◽  
Breeding Programs ◽  
Apple Breeding ◽  
Trait Loci ◽  
New Races

The major scab resistance gene Vf, extensively used in apple breeding programs, was recently overcome by the new races 6 and 7 of the fungal pathogen Venturia inaequalis. New, more durable, scab resistance genes are needed in apple breeding programs. F1 progeny derived from the cross between partially resistant apple cv. Discovery and apple hybrid ‘TN10-8’ were inoculated in the greenhouse with eight isolates of V. inaequalis, including isolates able to overcome Vf. One major resistance gene, Vg, and seven quantitative trait loci (QTL) were identified for resistance to these isolates. Three QTL on linkage group (LG)12, LG13, and LG15 were clearly isolate-specific. Another QTL on LG5 was detected with two isolates. Three QTL on LG1, LG2, and LG17 were identified with most isolates tested, but not with every isolate. The QTL on LG2 displayed alleles conferring different specificities. This QTL co-localized with the major scab resistance genes Vr and Vh8, whereas the QTL on LG1 colocalized with Vf. These results contribute to a better understanding of the genetic basis of the V. inaequalis-Malus × domestica interaction.

scholarly journals Influence of Corn (Zea maysL.) Cultivar Development on Grain Nutrient Concentration

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Carla Fernanda Ferreira ◽  
Antônio Carlos Vargas Motta ◽  
Stephen A. Prior ◽  
Carlos Bruno Reissman ◽  
Nicolas Z. dos Santos ◽  
...  
Keyword(s):  
Nutrient Concentration ◽  
High Yield ◽  
High Fertility ◽  
Breeding Programs ◽  
Nutrient Quality ◽  
Cultivar Development ◽  
Zn And Cu In ◽  
Corn Productivity ◽  
Climate Events

While corn productivity has been increased by the adoption of high-yield hybrids, there are concerns that increased grain potential may be associated with diminished grain nutrient concentration. Ten corn (Zea maysL.) cultivars representing five technological levels (landrace variety, commercial variety, and double, triple, and single cross-hybrids) were cropped on a Rhodic Ferralsol Eutric soil with high fertility in 2006 (dry year) and 2007 (normal year) in Rolândia County, Brazil. At maturity, grain was evaluated for concentrations of P, K, Ca, Mg, Fe, Mn, Zn, and Cu. In general, differences among cultivars were noted for all nutrients in both years. Concentrations of P, K, Fe, and Mn were lower in the dry year, while Ca, Mg, Cu, and Zn were higher. Soil water availability appeared to exert more influence on grain nutrient concentration than did cultivar development; nutrient removal due to grain harvest was also greatly influenced by rainfall patterns and their impact on corn productivity. Even though genetic differences were noted, which may be useful to breeding programs, long-term testing in subtropical environments will be required to clarify the interaction between genetics and climate events on grain nutrient quality and exportation.

scholarly journals Suppression of Pecan Scab by Nickel

HortScience ◽  
2012 ◽  
Vol 47 (4) ◽  
pp. 503-508 ◽  
Author(s):  
Bruce W. Wood ◽  
Charles C. Reilly ◽  
Clive H. Bock ◽  
Michael W. Hotchkiss
Keyword(s):  
Disease Severity ◽  
Economic Cost ◽  
Fruit Weight ◽  
Scab Resistance ◽  
Disease Assessment ◽  
Moderate Degree ◽  
Host Genotype ◽  
Pecan Scab ◽  
Reduce Disease Severity

The economic cost of pecan scab, caused by Fusicladium effusum G. Winter, can substantially limit profitability of pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivation in humid environments. Laboratory, greenhouse, and field studies found nickel (Ni) to inhibit growth of F. effusum and reduce disease severity on fruit and foliage of orchard trees. Nickel was toxic to the fungus in vitro at concentrations applied to orchard trees, and Ni sprays reduced scab severity on foliage of pecan seedlings in greenhouse experiments. Host genotype appears to influence Ni efficacy with fruit tissue of cultivars of intermediate resistance (i.e., ‘Desirable’) being most responsive to treatment and those most susceptible to scab (i.e., ‘Wichita’ and ‘Apache’) being least responsive. Addition of Ni as a nutritional supplement applied in combination with fungicides applied as air-blast sprays to commercial orchards reduced severity of scab on both leaves and fruit depending on cultivar and date of disease assessment (e.g., scab severity on fruit was reduced by 6% to 52% on ‘Desirable’ in an orchard setting). Nickel-supplemented fungicide sprays to ‘Desirable’ trees in commercial orchards also increased fruit weight and kernel filling, apparently from improved disease control. Although the efficacy of Ni was typically much less than that of triphenyltin hydroxide (TPTH), a standard fungicide used in commercial orchards, Ni treatment of tree canopies for increasing tree Ni nutrition slightly lowered disease severity. These studies establish that foliar Ni use in orchards potentially reduces severity of scab on foliage and fruit in scab-prone environments. The inclusion of Ni with fungicides for management of pecan scab might reduce disease severity over that conferred by fungicide alone, especially if targeted cultivars possess at least a moderate degree of scab resistance. Similar benefit from Ni sprays might also occur in host–fungi interactions involving other crops.

scholarly journals Early Differences in the Intensity of Alternate Bearing Among Selected Pistachio Genotypes

HortScience ◽  
2007 ◽  
Vol 42 (7) ◽  
pp. 1740-1743 ◽  
Author(s):  
Craig E. Kallsen ◽  
Dan E. Parfitt ◽  
Brent Holtz
Keyword(s):  
Similar Pattern ◽  
Female Parent ◽  
San Joaquin Valley ◽  
Breeding Program ◽  
Pistacia Vera ◽  
Kern County ◽  
Alternate Bearing ◽  
Breeding Programs ◽  
Old Trees

Alternate bearing (alternating years with high and low yields) is a prominent characteristic of ‘Kerman’ pistachio (Pistacia vera L.), the primary California cultivar. The degree of alternate bearing is described by alternate bearing index values from 0 (identical yields every year) to 1 (complete alternate bearing). Two separate and replicated trials designed to evaluate selections from a breeding program were conducted in the southwest (Kern County) and northeast (Madera County) areas of the San Joaquin Valley of California. Yields from the scion genotypes ‘Kerman’, ‘Golden Hills’, ‘Lost Hills’, ‘B5-8’, and ‘B19-1’ on PG1 rootstock were measured from 5- to 9-year-old trees in Kern County and from 5- to 7-year-old ‘Kerman’, ‘Golden Hills’, ‘Lost Hills’, and ‘B5-8’ trees on PG1 and UCB1 rootstock in Madera County. In Kern County, average annual yields among genotypes varied from a low of 208 to a high of 5273 kg·ha−1. Differences in the alternate bearing indices among genotypes were significant and ranged from 0.10 for ‘Lost Hills’ to 0.80 for ‘B19-1’. A similar pattern was observed for alternate bearing indices at the Madera County trial. In this younger trial, scion genotype had more influence on alternate bearing indices than did rootstock. Marked differences in the intensity of alternate bearing of young trees in these two trials suggest that alternate bearing might be amenable to selection in breeding programs. However, the observation that ‘B5-8’, with an alternate bearing index of 0.74, varied significantly from its female parent ‘Kerman’ at 0.36 suggests that inheritance is complex.

scholarly journals Production Characteristics of the United States Pecan Industry

1993 ◽  
Vol 118 (4) ◽  
pp. 538-545 ◽  
Author(s):  
Bruce W. Wood
Keyword(s):  
South Carolina ◽  
National Level ◽  
The United States ◽  
Alternate Bearing ◽  
Nut Production ◽  
National Production ◽  
Practical Tool ◽  
Univariate Polynomial ◽  
State Production ◽  
Highly Correlated

The cyclic, alternate bearing and correlative aspects of U.S. produced pecan [Carya illinoinensis (Wangenh.) K. Koch] nuts are characterized. An attempt to forecast production using stepwise autoregressive techniques identified a national level biennial cycle for cultivar (CV) and seedling (SC) class nuts and a novemennial (9 year) cycle for SG class nuts. The intensity of the biennial cycle at the national level has generally been low to moderate over the last 50 years for CV and SG class nuts with no clear time trend being expressed. During the most recent years (1979-1991), national production of CV class nuts has not exhibited pronounced bienniality, whereas that of SG class nuts exhibited a moderate bienniality. The nature of the the irregularity of cycling of U.S. and state production appears to nullify the use of univariate polynomial equations as a practical tool for accurately forecasting nut production. Nut production within individual states was also cyclic, with 2-, 3-, 5, 6-, 10-, 12-, 14-, 15-, and 16-year cycles, depending on state and nut class. The most intense contemporary biennial cycles for CV class nuts were from Oklahoma, South Carolina, and North Carolina, whereas cycling of SG class nuts was most intense in Texas and Oklahoma. Correlations of production within and among states indicated that most interrelationships are relatively weak; however, national production of CV class nuts are highly correlated (r = 0.96) with the production of CV class nuts in Georgia, whereas that of SG class nuts is most correlated with that of Louisiana.

scholarly journals Trends in Stone Fruit Cultivar Development

2005 ◽  
Vol 15 (3) ◽  
pp. 494-500 ◽  
Author(s):  
David H. Byrne
Keyword(s):  
Public Sector ◽  
Stone Fruit ◽  
Agricultural Chemicals ◽  
Fresh Market ◽  
Breeding Programs ◽  
Global Marketing ◽  
The Public ◽  
Cultivar Development ◽  
World Markets ◽  
The World

Despite the hundreds of existing stone fruit (Prunus spp.) cultivars used for fresh market, there is a continuing need to develop new stone fruit cultivars as the requirements of the industry change. Over the last 20 years there has been a shift toward private breeding as the public sector decreases its support of these long-range programs. As a result there are fewer public breeding programs and many of those still operating protect their releases and partially fund their programs with royalty payments. Other trends that are shaping the development of new stone fruit cultivars are a need for smaller or more easily managed tree architecture, a trend toward the use of fewer agricultural chemicals, the expansion of production zones into the milder winter zones to allow year-round availability of stone fruit, a general diversification of fruit types being marketed, the increased awareness of the health benefits of fruit consumption, the need for better and more consistent quality, and given the global marketing of these fruit the increased need for enhanced postharvest qualities. The breeding programs of the world are responding to these trends and working toward developing the cultivars for the world markets of the future.

scholarly journals A Comparison of Ground-Based Air-Blast Sprayer and Aircraft Application of Fungicides to Manage Scab in Tall Pecan Trees

Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1675-1684
Author(s):  
Clive H. Bock ◽  
Michael W. Hotchkiss
Keyword(s):  
Linear Relationship ◽  
Spray Deposition ◽  
Negative Relationship ◽  
Good Control ◽  
Air Blast ◽  
Kernel Quality ◽  
Pecan Scab ◽  
The Impact ◽  
Aircraft Application ◽  
Insight Into

Pecan scab (caused by Venturia effusa) is a destructive disease of pecan in the southeastern United States. Susceptible cultivars must be sprayed with fungicide every 10 to 21 days to ensure yield and kernel quality. Fungicide is most often applied using large orchard air-blast sprayers. Pecan trees grow tall, and air-blast sprays result in a gradient in spray deposition and consequently of scab. Aerial fungicide application is also practiced. Disease distribution and spray deposition of the two methods have not been compared but will provide information aiding decisions on spray application methods. We compared air-blast, aerial, and air-blast + aerial applications for efficacy controlling scab at five heights in the canopy of 25-m cultivar Schley pecan trees. There was a negative relationship between scab severity and height in control trees, a positive linear relationship with height in air-blast treated trees, and a generally negative linear relationship between scab severity and height in aerially treated trees. Air-blast + aerial treatments resulted in low severity of scab at all heights. Spray deposition on water-sensitive cards indicated a declining gradient with height using an air-blast sprayer, whereas aerial applications resulted in a low deposition at all sample heights. Air-blast sprays tended to result in less good control at heights >12.5 m, and aerially treated trees at ≤7.5 m. The results provide insight into the efficacy and advantages of these methods for applying fungicide to control scab in tall pecan trees; further research is needed to better understand the impact of frequency and timing of these two methods.

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