Field Evaluations of Leaf Spot Resistance and Yield in Peanut Genotypes in the United States and Bolivia

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.

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Late Leaf Spot Severity and Yield of New Peanut Breeding Lines and Cultivars Grown Without Fungicides

Plant Disease ◽

10.1094/pdis-02-17-0165-re ◽

2017 ◽

Vol 101 (11) ◽

pp. 1843-1850 ◽

Cited By ~ 3

Author(s):

Brian S. Jordan ◽

Albert K. Culbreath ◽

Timothy B. Brenneman ◽

Robert C. Kemerait ◽

William D. Branch

Keyword(s):

Leaf Spot ◽

Vegetation Index ◽

Field Experiments ◽

Organic Production ◽

Canopy Reflectance ◽

Cercospora Arachidicola ◽

Early Season ◽

Late Leaf Spot ◽

Breeding Lines ◽

Width Measurements

Peanut (Arachis hypogaea) cultivars with resistance or tolerance to Cercospora arachidicola and/or Cercosporidium personatum, the causes of early and late leaf spot, respectively, are needed for organic production in the southeastern U.S. To determine the potential of new breeding lines for use in such production systems, field experiments were conducted in Tifton, GA, in 2014 and 2015 in which nine breeding lines and two cultivars, Georgia-06G and Georgia-12Y, were grown without foliar fungicide applications. In one set of trials, cultivar Georgia-12Y and most of the breeding lines evaluated had early season vigor ratings, early-season canopy width measurements, final plant populations, and pod yield that were greater than those of standard cultivar Georgia-06G. In those trials, final late leaf spot Florida scale ratings were lower and canopy reflectance measured as the normalized difference vegetation index (NDVI), was higher all the breeding lines than those of Georgia-06G. In another set of trials, two of those same breeding lines had final late leaf spot ratings similar to those of Georgia-12Y in 2014, whereas in 2015, six of those breeding lines had final leaf spot ratings that were lower than those of Georgia-12Y. Yields were similar for Georgia-12Y and all the breeding lines in the Gibbs Farm trials. Across years and breeding lines at the Lang Farm, the relationship between visual estimates of defoliation and NDVI was described by a two sector piecewise regression with NDVI decreasing more rapidly with increasing defoliation above approximately 89%. The utility of NDVI for spot comparisons among breeding lines appears to be limited to situations where there are differences in defoliation. Georgia-12Y and multiple breeding lines evaluated show potential for use in situations such as organic production where acceptable fungicides available for seed treatment and leaf spot control are limited.

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Effect of In-Furrow and Early-Season Banded Applications of Fungicides on Incidence of Early Leaf Spot of Peanut

Plant Health Progress ◽

10.1094/php-rs-15-0029 ◽

2015 ◽

Vol 16 (4) ◽

pp. 225-229

Author(s):

Albert K. Culbreath ◽

Robert C. Kemerait ◽

Yun-Ching Tsai ◽

Timothy B. Brenneman ◽

Katherine L. Stevenson ◽

...

Keyword(s):

Arachis Hypogaea ◽

Leaf Spot ◽

Field Experiments ◽

Disease Incidence ◽

Cercospora Arachidicola ◽

Early Season ◽

Fungicide Application

Field experiments were conducted in Tifton, GA, in 2012-2014 to determine the effect of in-furrow applications of prothioconazole and early-season banded applications of prothioconazole or pyraclostrobin on incidence of early leaf spot (Cercospora arachidicola) of peanut (Arachis hypogaea). In each year, border rows were planted in May as a source of inoculum for plants in the treatment plots. Plots were planted in August or September after epidemics of early leaf spot were severe in the border plots. Fungicide application regimes included two rates (100 and 200 g a.i./ha) of prothioconazole applied in-furrow at planting, and 200 g a.i./ha of prothioconazole or 164 g a.i./ha of pyraclostrobin applied concentrated in a 30-cm band 21 days after planting (DAP). Incidence (percent of leaflets with one or more leaf spot) of early leaf spot was monitored until 54 to 57 days after planting in each year. In all years, disease incidence was below 10% at 28 DAP in plots treated with 200 g a.i./ha of prothioconazole in-furrow compared to over 40% in nontreated plots at the same time. In-furrow applications of 100 g a.i./ha of prothioconazole were less effective, but suppressed leaf spot incidence compared to the control. Banded applications of either fungicide at 21 DAP resulted in a decrease in leaf spot incidence, and prevented increase in leaf spot incidence for 19 days or longer. Accepted for publication 30 November 2015. Published 3 December 2015.

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Evaluation of Host Resistance to Botrytis Bunch Rot in Vitis spp. and Its Correlation with Botrytis Leaf Spot

HortScience ◽

10.21273/hortsci12655-17 ◽

2018 ◽

Vol 53 (2) ◽

pp. 204-207 ◽

Cited By ~ 3

Author(s):

Rachel P. Naegele

Keyword(s):

Fruit Quality ◽

Host Resistance ◽

Leaf Spot ◽

Disease Incidence ◽

The United States ◽

Soluble Solids ◽

Postharvest Disease ◽

Breeding Lines ◽

Bunch Rot ◽

Moderate Resistance

Botrytis cinerea, the causal agent of Botrytis bunch rot and gray mold, is the number one postharvest disease of fresh grapes in the United States. Fungicide applications are used to manage the disease, but fungicide-resistant isolates are common and postharvest losses occur annually. Host resistance is needed for long-term management of the disease. Sources of resistance in grape have been identified, but often have poor fruit quality. In this study, 27 grape lines (cultigens and species), including high fruit–quality Vitis vinifera, were evaluated for fruit and leaf susceptibility to two isolates of B. cinerea. No significant differences in virulence or pathogenicity were detected between the two isolates, but differences in disease incidence were evident among lines in leaves and berries. Most V. vinifera cultivars evaluated had high disease incidence in berries, whereas complex hybrids, Vitis aestivalus and Vitis arizonica, had low- to moderate disease incidence. Two V. vinifera breeding lines had moderate susceptibility (<50% disease) to Botrytis bunch rot when inoculated with either isolate. Only one V. vinifera line had little (<5%) to no berry or leaf disease when inoculated with either isolate. Moderate resistance (10% to 25%) was detected in Vitis spp., and a single V. vinifera line. Correlations were examined among soluble solids, leaf susceptibility, and fruit susceptibility. No correlations between soluble solids and disease susceptibility (leaves or berries) were identified, but moderate correlations between leaf and berry susceptibility were observed. Moderate resistance to Botrytis bunch rot and leaf spot were detected in Vitis breeding lines, suggesting these may be useful for developing grape cultivars with high fruit quality and resistance to B. cinerea.

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Diallel Analysis of Early Leaf Spot (Cercospora arachidicola Hori) Disease Resistance in Groundnut

Agronomy ◽

10.3390/agronomy9010015 ◽

2019 ◽

Vol 9 (1) ◽

pp. 15 ◽

Cited By ~ 2

Author(s):

Adama Zongo ◽

Abdourasmane K. Konate ◽

Kadidia Koïta ◽

Mahamadou Sawadogo ◽

Philippe Sankara ◽

...

Keyword(s):

Disease Resistance ◽

Leaf Spot ◽

Gene Action ◽

Block Design ◽

Regression Line ◽

Cercospora Arachidicola ◽

Additive Gene Action ◽

Progress Curve ◽

Additive Gene ◽

Resistance Traits

Early leaf spot (ELS) is one of the major biotic constraints of groundnut production in West and Central Africa. A study using 6 × 6 F2 full diallel populations from six parents (NAMA, B188, PC79-79, QH243C, TS32-1, and CN94C) was conducted to assess the mode of inheritance of ELS resistance traits. The F2 and parents were grown in a randomized complete block design with three replications. Data was collected on ELS disease severity, and an area under disease progress curve (AUDPC) was estimated. The results revealed that additive and non-additive gene actions were involved in the inheritance of the ELS resistance traits, but additive gene action was predominant. Significant reciprocal cross effect was observed, suggesting cytoplasmic effect on ELS resistance. Graphical analysis also revealed the predominance of additive gene action for ELS resistance. The results suggest that early generation selection should be effective for ELS resistance. Looking at the distribution of array points along with the regression line, parental lines NAMA, PC79-79, and B188 would be suitable as good donors in an ELS disease resistance breeding program.

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First Report of Gray Leaf Spot on Perennial Ryegrass Turf in California

Plant Disease ◽

10.1094/pdis.2002.86.1.75c ◽

2002 ◽

Vol 86 (1) ◽

pp. 75-75 ◽

Cited By ~ 19

Author(s):

W. Uddin ◽

G. Viji ◽

L. Stowell

Keyword(s):

United States ◽

Perennial Ryegrass ◽

Leaf Spot ◽

Disease Incidence ◽

The United States ◽

Gray Leaf Spot ◽

Water Soluble ◽

Distilled Water ◽

First Report ◽

Polyethylene Bags

Gray leaf spot of perennial ryegrass (Lolium perenne L.) turf was first reported in the United States in 1991. The disease epidemic was primarily confined to golf course fairways in southeastern Pennsylvania (1). Subsequently, moderate to severe outbreaks of gray leaf spot occurred in perennial ryegrass fairways and roughs in numerous locations throughout the eastern and midwestern United States. In August 2001, a serious decline of perennial ryegrass turf was observed in a bermudagrass (Cynodon dactylon (L.) Pers) baseball field in Dodger Stadium in Los Angeles, CA, that had been overseeded with perennial ryegrass. The bermudagrass turf was not affected. The perennial ryegrass turf developed necrotic lesions that resulted in blighting of leaf blades. In laboratory assays, Pyricularia grisea (Cooke) Sacc., was consistently isolated from symptomatic ryegrass blades from turf samples collected from the site. Of the 12 P. grisea isolates collected from the assayed leaf blades, five isolates were selected for a pathogenicity assay. Twenty-five ‘Legacy II’ perennial ryegrass plants were grown from seeds in 4 × 4 in.-plastic pots, (10 × 10 cm) which were filled to 1 cm below the rim with granular calcine clay medium (Turface MVP, Allied Industrial Material Corp., Buffalo Grove, IL). Three weeks after seeding, plants were fertilized with a water-soluble 20-20-20 N-P-K fertilizer (1.3 g/liter of water) once per week. Treatments (isolates of P. grisea and a control) were arranged as a randomized complete block design with five replications. Five-week-old plants were sprayed with an aqueous suspension of P. grisea conidia (≈5 × 104 conidia per ml of sterilized distilled water with 0.1% Tween 20) using an atomizer until the leaves were completely wet. Plants sprayed with sterilized distilled water served as the control. After inoculation, individual pots were covered with clear polyethylene bags and placed in a controlled environment chamber maintained at 28°C and continuous fluorescent light (88 μE m-2 s-1). Four days after inoculation, necrotic lesions (<2 mm diameter) developed on ryegrass blades inoculated with each isolate of P. grisea. Lesions did not develop on leaves of control plants. Seven days after inoculation, the polyethylene bags were removed, and 50 symptomatic blades from each pot were collected, and disease incidence (percent infected leaves) and severity (index 0 to 10; 0 = none, 10 = >90% of the leaf blade necrotic ) were assessed. P. grisea was isolated from symptomatic leaves of plants inoculated with the fungus. Disease incidence and severity on inoculated plants were 92 to 96% and 8.8 to 10, respectively. There were no significant differences in disease incidence and severity (P = 0.05) among the isolates of P. grisea included in the test. To our knowledge, this is the first report of gray leaf spot of perennial ryegrass turf in California. Reference: (1) P. J. Landschoot and B. F. Hoyland. Plant Dis. 76:1280, 1992.

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Field evaluation and components of peanut rust resistance of newly developed breeding lines

Peanut Science ◽

10.3146/ps18-4.1 ◽

2019 ◽

Vol 46 (1) ◽

pp. 22-36

Author(s):

I.L. Power ◽

B.L. Tillman ◽

T.B. Brenneman ◽

R.C. Kemerait ◽

K L. Stevenson ◽

...

Keyword(s):

Latent Period ◽

Rust Resistance ◽

Field Experiments ◽

The United States ◽

Growth Chamber ◽

Breeding Lines ◽

Plant Introductions ◽

Progress Curve ◽

Chamber Studies ◽

Growth Chamber Studies

ABSTRACT Field, greenhouse, and growth chamber experiments were conducted to determine the level of resistance to Puccinia arachidis Speg. in newly developed breeding lines of peanut (Arachis hypogaea L.). These lines were developed in the UF150 project of the Peanut Collaborative Research and Support Program (Peanut CRSP) as part of the United States Agency for International Development (USAID). Field experiments were carried out in Citra, FL and Tifton, GA from 2010 to 2013. Five genotypes Tifrust-10 and Tifrust-13, and CRSP breeding lines PTBOL3-3, 97x36-HO2-1-B2G-3-1-2-2, and BOL3-7 had the lowest standardized area under the disease progress curve and final disease severity score for rust. The CRSP breeding lines 97x36-HO2-1-B2G-3-1-2-2 and BOL3-7 also appeared to be highly resistant to late leaf spot, caused by Cercosporidium personatum (Berk & M. A. Curtis Deighton). In growth chamber studies, genotypes with longer latent periods generally had lower infection frequencies at 7, 11, and 16 d after inoculation, and smaller percent diseased areas. Latent period and percent diseased area were significantly correlated with stAUDPC. CRSP breeding lines 97x36-HO2-1-B2G-3-1-2-2 and BOL3-7, and plant introductions PI562530, PI568164, and PI298115, were among the genotypes with the lower scores for these components. Several genotypes with multiple disease resistance in different environments and under high disease pressure were identified in these studies. These results indicate sources of rust resistance in the CRSP breeding lines, including several genotypes that could be used as parents in peanut germplasm enhancement programs, and indicate that latent period, percent diseased area, and lesion diameter may be used as indicators for rust resistance in growth chamber studies.

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Genetics and Breeding for Glandless Upland Cotton With Improved Yield Potential and Disease Resistance: A Review

Frontiers in Plant Science ◽

10.3389/fpls.2021.753426 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jinfa Zhang ◽

Tom Wedegaertner

Keyword(s):

United States ◽

Disease Resistance ◽

New Mexico ◽

Upland Cotton ◽

Fiber Quality ◽

The United States ◽

Yield Potential ◽

Current Status ◽

Cotton Production ◽

Glandless Cotton

Glandless cotton (devoid of toxic gossypol) can be grown as a triple-purpose crop for fiber, feeds, and food (as an oil and protein source). However, its sensitivity to insect pests and its low yield due to the lack of breeding activities has prevented the realization of its potential in commercial seed production and utilization. Since the mid-1990s, the commercialization of bollworm and budworm resistant Bt cotton and the eradication of boll weevils and pink bollworms have provided an opportunity to revitalize glandless cotton production in the United States. The objectives of this study were to review the current status of genetics and breeding for glandless cotton, with a focus on the progress in breeding for glandless Upland cotton in New Mexico, United States. Because there existed a 10–20% yield gap between the best existing glandless germplasm and commercial Upland cultivars, the breeding of glandless Upland cultivars with improved yield and disease resistance was initiated at the New Mexico State University more than a decade ago. As a result, three glandless Upland cultivars, i.e., long-staple Acala 1517-18 GLS, medium staple NuMex COT 15 GLS, and NuMex COT 17 GLS with Fusarium wilt race 4 resistance were released. However, to compete with the current commercial glanded cotton, more breeding efforts are urgently needed to introduce different glandless traits (natural mutations, transgenic or genome-editing) into elite cotton backgrounds with high yields and desirable fiber quality.

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Novel Sources of Wheat Head Blast Resistance in Modern Breeding Lines and Wheat Wild Relatives

Plant Disease ◽

10.1094/pdis-05-19-0985-re ◽

2020 ◽

Vol 104 (1) ◽

pp. 35-43 ◽

Cited By ~ 9

Author(s):

Giovana Cruppe ◽

Christian D. Cruz ◽

Gary Peterson ◽

Kerry Pedley ◽

Mohammad Asif ◽

...

Keyword(s):

Field Experiments ◽

Blast Resistance ◽

Disease Incidence ◽

Low Frequency ◽

The United States ◽

Wild Relatives ◽

Sources Of Resistance ◽

Aegilops Ventricosa ◽

Breeding Lines ◽

Wheat Wild Relatives

Wheat head blast (WHB), caused by the fungus Magnaporthe oryzae pathotype triticum, is a devastating disease affecting South America and South Asia. Despite 30 years of intensive effort, the 2NVS translocation from Aegilops ventricosa contains the only useful source of resistance to WHB effective against M. oryzae triticum isolates. The objective of this study was to identify non-2NVS sources of resistance to WHB among elite cultivars, breeding lines, landraces, and wild-relative accessions. Over 780 accessions were evaluated under field and greenhouse conditions in Bolivia, greenhouse conditions in Brazil, and at two biosafety level-3 laboratories in the United States. The M. oryzae triticum isolates B-71 (2012), 008 (2015), and 16MoT001 (2016) were used for controlled experiments, while isolate 008 was used for field experiments. Resistant and susceptible checks were included in all experiments. Under field conditions, susceptible spreaders were inoculated at the tillering stage to guarantee sufficient inoculum. Disease incidence and severity were evaluated as the average rating for each 1-m-row plot. Under controlled conditions, heads were inoculated after full emergence and individually rated for percentage of diseased spikelets. The diagnostic marker Ventriup-LN2 was used to test for the presence of the 2NVS translocation. Four non-2NVS spring wheat International Maize and Wheat Improvement Center breeding lines (CM22, CM49, CM52, and CM61) and four wheat wild-relatives (A. tauschii TA10142, TA1624, TA1667, and TA10140) were identified as resistant (<5% of severity) or moderately resistant (5 to <25% severity) to WHB. Experiments conducted at the seedling stage showed little correlation with disease severity at the head stage. M. oryzae triticum isolate 16MoT001 was significantly more aggressive against 2NVS-based varieties. The low frequency of WHB resistance and the increase in aggressiveness of newer M. oryzae triticum isolates highlight the threat that the disease poses to wheat production worldwide and the urgent need to identify and characterize new resistance genes that can be used in breeding for durably resistant varieties.

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Evaluation of a Weather-Based Spray Advisory for Management of Early Leaf Spot of Peanut in Oklahoma1

Peanut Science ◽

10.3146/i0095-3679-21-2-10 ◽

1994 ◽

Vol 21 (2) ◽

pp. 115-121 ◽

Cited By ~ 8

Author(s):

J. P. Damicone ◽

K. E. Jackson ◽

J. R. Sholar ◽

M. S. Gregory

Keyword(s):

Post Infection ◽

Leaf Spot ◽

Disease Incidence ◽

Cercospora Arachidicola ◽

Advisory Program ◽

Arachis Hypogea ◽

Progress Curve ◽

Weather Stations ◽

Improved Performance ◽

And Control

Abstract A simplified version of the weather-based advisory program developed by Parvin, Smith, and Crosby (PSC) for scheduling fungicide sprays for management of early leaf spot (Cercospora arachidicola Hori) of peanut (Arachis hypogea L.) was evaluated under various productions systems in Oklahoma from 1990-1992. Over eight trials with spanish cultivars, the number of sprays per season averaged 5.7 for the 14-d schedule and 4.0 for the advisory program. Final disease incidence (symptomatic and defoliated leaflets) with the fungicide chlorothalonil (1.26 kg/ha) averaged 15% for the 14-d schedule, 34% for the advisory program, and 77% for the control. However, disease incidence (75%) and defoliation (50%) approached unacceptable levels on the spanish cultivars in some trials. In six trials with runner cultivars, the number of sprays averaged 6.7 for the 14-d schedule and 4.7 for the advisory program. Final disease incidence with chlorothalonil on the runner cultivars averaged 5% for the 14-d schedule, 14% for the advisory program, and 68% in the control. Yields did not differ in any of the 14 trials between the advisory and 14-d programs using chlorothalonil. Yields averaged 3015, 3003, and 2303 kg/ha for spanish cultivars and 4108, 3855, and 3066 kg/ha for runner cultivars with the 14-d schedule, advisory program, and control, respectively. The advisory program was effective in irrigated trials where weather stations were deployed either under or outside the influence of irrigation. The fungicides tebuconazole at 0.14 kg/ha and propiconazole at 0.13 kg/ha generally provided better leaf spot control with the advisory program than chlorothalonil. The post-infection activity of these fungicides was observed in one trial and probably accounts for their improved performance. Yields were reduced and leaf spot incidence was high where tank mixes of benomyl (0.28 kg/ha) or thiophanatemethyl (0.38 kg/ha) plus mancozeb (1.68 kg/ha) were used with the advisory program. Area under the disease progress curve, leaf spot incidence, and defoliation in the controls were lower for runner than for spanish cultivars at sites where both market types were planted in adjacent trials. Fungicides applied according to the advisory program provided better leaf spot control on the runner cultivars. Results showed the need for a weather-based advisory which allows greater levels of leaf spot control on spanish cultivars than the PSC advisory.

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(274) Inter- and Intra-specific Variation in Yield and Quality Traits of Chile Pepper Breeding Lines

HortScience ◽

10.21273/hortsci.40.4.1021a ◽

2005 ◽

Vol 40 (4) ◽

pp. 1021A-1021

Author(s):

Reddy R. Chinthakuntla ◽

Frank Matta ◽

Rao S. Mentreddy ◽

Umesh Reddy ◽

Padmavathi Nimmakayala ◽

...

Keyword(s):

United States ◽

Agronomic Traits ◽

Genotypic Variation ◽

The United States ◽

Yield Potential ◽

High Yield ◽

Breeding Lines ◽

Percent Germination ◽

Specific Variation ◽

Chile Peppers

Chilepepper (Capsicum spp.) is the third most important vegetable crop in the United States. The market value of chile peppers for spices and condiments exceeds $650 million per year. With a growing Hispanic population across the United States, the demand for high yielding, good quality cayenne pepper continues to increase. In order to fulfill this niche market, a study has been initiated to develop pepper varieties that combine high yield potential with superior agronomic traits, including insect and disease resistance, and fruit characteristics, using molecular marker assisted breeding/selection. In preliminary trials, several F1 generations were created through inter- and intra-specific crosses among 220 germplasm lines belonging to six Capsicumsp. in the greenhouse. Selected F1 progeny, parent lines, and selected accessions were planted in single-row field plots the following summer. The crossing success was higher within species than between. The genotypic variation was significant for all parameters examined. The average percent germination (81.1) of F1 progeny was 32% and 45% higher than that of the parent lines and selected accessions, respectively. The F1 progeny were shorter in height; more vigorous in growth, flowered early, and with fewer, but heavier, fruits per plant out-yielded the parent lines and accessions by 50% and 120%, respectively. The study showed a marked heterosis in F1 progeny compared to the parent lines and accessions. Microsatellite genotyping to estimate genetic diversity and validation of markers that are linked to various traits is in progress and will be discussed in the presentation.

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