Genotype ́ Environment Interaction and Stability Analysis for Watermelon Fruit Yield in the United States

One of the major breeding objectives for watermelon (Citrullus lanatus [Thumb.] Matsum & Nakai) is improved fruit yield. High yielding genotypes have been identified, so we measured their stability for fruit yield and yield components over diverse environments. The objectives of this study were to (i) evaluate the yield of watermelon genotypes over years and locations, (ii) identify genotypes with high stability for yield, and (iii) measure the correlations among univariate and multivariate stability statistics. A diverse set of 40 genotypes was evaluated over 3 yr (2009, 2010, and 2011) and eight locations across the southern United States in replicated trials. Yield traits were evaluated over multiple harvests, and measured as marketable yield, fruit count, percentage cull fruit, percentage early fruit, and fruit size. There were strong effects of environment as well as genotype ́ environment interaction (G ́E) on watermelon yield traits. Based on multiple stability measures, genotypes were classified as stable or unstable for yield. There was an advantage of hybrids over inbreds for yield components in both performance and responsiveness to favorable environments. Cultivars Big Crimson and Legacy are inbred lines with high yield and stability. A significant (P < 0.001) and positive correlation was measured for Shukla’s stability variance (si 2), Shukla’s squared hat (ŝi 2), Wricke’s ecovalence (Wi), and deviation from regression (Sd) for all the traits evaluated in this study. M. Dia and T.C. Wehner, Dep. of Horticultural Science, North Carolina State Univ., Campus Box 7609, Raleigh, NC 27695-7609; R. Hassell, Clemson University, Coastal Research and Education Center, 2700 Savannah Hwy, Charleston, SC 29414; D.S. Price, Georgia County Extension, SW District, 110 West 13th Ave, Suite C, Cordele, GA 31015; G.E. Boyhan, University of Georgia, Dep. of Hort., 1111 Miller Plant Science Bldg., Athens, GA 30602; S. Olson, North Florida REC, Univ. of Florida, 155 Research Road, Quincy, FL 32351-5677; S. King, Texas A&M University, Dep. of Hort. Sci., 1500 Research Pkwy, Ste A120, College Station, TX 77845; A.R. Davis, USDA-ARS, 911 East Highway 3, Lane, OK 74555; G.E. Tolla, Monsanto/Seminis Veg Seeds, 37437 State Hwy 16, Woodland, CA 95695. Received 12 Oct. 2015. Accepted 2 Feb. 2016. *Corresponding author ([email protected]). Abbreviations: AEC, average environment coordinate; AMMI, additive main effects and multiplicative interaction; bi, linear regression coefficient; CI, Clinton, NC; FL, Quincy, FL; GA, Cordele, GA; GGE, genotype main effects plus genotypic ́ environment interaction effect; GGL, genotype main effects plus genotypic ́ location interaction effect; G ́E, Genotype ́ environment interaction; G01 or 1, AU-Jubilant; G02 or 2, Allsweet; G03 or 3, Big Crimson; G04 or 4, Black Diamond; G05 or 5, Calhoun Gray; G06 or 6, Calsweet; G07 or 7, Carolina Cross#183; G08 or 8, Charleston Gray; G09 or 9, Congo; G10 or 10, Crimson Sweet; G11 or 11, Desert King; G12 or 12, Early Arizona; G13 or 13, Early Canada; G14 or 14, Fiesta F1; G15 or 15, Georgia Rattlesnake; G16 or 16, Golden Midget; G17 or 17, Graybelle; G18 or 18, Hopi Red Flesh; G19 or 19, Jubilee; G20 or 20, King & Queen; G21 or 21, Legacy; G22 or 22, Mickylee; G23 or 23, Minilee; G24 or 24, Mountain Hoosier; G25 or 25, NC Giant; G26 or 26, Navajo Sweet; G27 or 27, Peacock WR-60; G28 or 28, Quetzali; G29 or 29, Regency F1; G30 or 30, Royal Flush F1; G31 or 31, Sangria F1; G32 or 32, Starbrite F1; G33 or 33, Stars-N-Stripes F1; G34 or 34, Stone Mountain; G35 or 35, Sugar Baby; G36 or 36, Sugarlee; G37 or 37, Sweet Princess; G38 or 38, Tendersweet OF; G39 or 39, Tom Watson; G40 or 40, Yellow Crimson; KN, Kinston, NC; M, trait mean; OK, Lane, OK; PC, principal component; SC, Charleston, SC; SVP, singular value partitioning; TX, College Station, TX; CA, Woodland, CA; si 2, Shukla’s stability variance; Ŝi 2, Shukla’s squared hat; Sd, deviation from regression; Wi, Wricke’s ecovalence; YSi, Kang’s stability statistic Published in Crop Sci. 56:1645–1661 (2016). doi: 10.2135/cropsci2015.10.0625 © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved. Published June 15, 2016