EVALUATION OF PECAN CULTIVARS IN NORTH FLORIDA FROM 1989 TO 19961

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1 Proc. Fla. State Hort. Soc. 09: EVALUATION OF PECAN CULTIVARS IN NORTH FLORIDA FROM 989 TO 996 P. C. Andersen North Florida Research and Education Center University of Florida Quincy, Florida 5 Additional index words. Carya illinoenensis, yield, quality, leaf diseases, nut diseases. Abstract Twenty six cultivars of ecan [Carya illinoenensis (Wagenh.) K. Koch] have been evaluated at the North Fla. Res. Ed. Center (NFREC)-Monticello from 989 to 996. Yield (er centage of full cro), resistance to leaf and nut diseases (main ly ecan scab) and resistance to limb breakage were estimated on to 0 trees of each cultivar. Average yield from 989 to 996 was % of a full cro across all cultivars; only 'Curtis' and 'Moreland' averaged more than 50% of a full cro. Resis tance to leaf diseases varied greatly among cultivars, and was highest for 'Moreland', 'Curtis', and 'Melrose'. Based uon yield, nut size, ercentage kernel, resistance to leaf and nut diseases and recocity highly recommended cultivars for north Florida include 'Cae Fear', 'Elliot' and 'Moreland'; rec ommended cultivars include 'Curtis' and 'Sumner'. 'Desirable', 'Gloria Grande', 'Kiowa' and 'Stuart' are conditionally recom mended. 'Jackson', Kernodle', 'Melrose' and 'Owens' are rec ommended for trial since they have erformed well at the NFREC-Monticello, but have not been adequately tested at oth er locations. The southeastern United States (and articularly Geor gia) is the major ecan roducing region in the United States and in the world. High humidity and high summer rainfall has limited the range of accetable cultivars for the southeast ern United States due to the difficulty in controlling ecan scab (Cladosorium carigenum Ell et Lang.). The recent intro duction of new high yielding, scab suscetible cultivars such as Wichita or Western Schley has given the southwestern Unit ed States a cometitive advantage over the Southeast. Imed iments to the culture of ecans in the southeastern United States have included: ) lack of new high yielding cultivars that are scab-resistant; ) lack of tree size control and suitable dwarfing rootstocks; ) lack of consistent yield due to alter nate bearing; ) ineffective marketing strategies, and; 5) com etition from other nut cros (walnuts, almonds, istachios) that are more successfully marketed (Andersen 995). Unusual climatic conditions during the last several years have had a negative imact on ecan roduction in Florida and in the Southeast. In north Florida severe winter freezes, untimely late sring frosts, cloudy/hazy atmosheric condi tions during the growing season, erratic atterns of reciita tion and intense disease ressures have contributed to low yields and quality over the last several years. For examle, the entire ecan cro at the NFREC-Monticello was lost in 990 due to a late sring frost. Only two cultivars in 99 and one cultivar in 99 and 995 out of 6 roduced at least one-half a full cro at the NFREC-Monticello. In 99 reciitation was erratic, while in 99 over 88 inches of rain fell between January and October. Weather conditions were more favor able during 995, but remature defoliation during 99 had Florida Agricultural Exeriment Station Journal Series No. N-OO. a carry over effect the following year. By contrast, during 996 yield was fair to for most cultivars of ecan at the NFREC-Monticello. In the southeastern ecan belt, disease suscetibility has become of aramount concern. Pecan scab is the disease of major imortance where it infects both leaves and nuts. Ahids have been the major insect est of ecan; however, re cently (since 99) imorted secies of ladybug beetles and other natural enemies have rovided adequate control of ahid oulations and chemical control has generally not been required. Pecan breeding and cultivar testing is a long-term invest ment. Pecan trees are not recocious and it requires 5 to 0 years after a cross is made until the resultant hybrid can be evaluated (Madden 968). In addition, the resistance of a giv en ecan cultivar to insects and diseases varies and generally declines over time. These facts underscore the need for long term evaluation and testing of ecan cultivars at various loca tions throughout the United States. Materials and Methods At the NFREC-Monticello 6 ecan cultivars have been evaluated from 989 to 996. Trees generally received fungi cides (Suer Tin, Orbit, Tilt, etc.) ca. once a month or once every two months from Aril through Setember to hel con trol leaf diseases. Insecticides were generally not alied to most blocks in any year. Sulemental irrigation was general ly not rovided. Data were collected on to 0 trees of each cultivar. Trees were at least years old in 989. Yields were rated as the ercentage of maximum yields obtainable for a given tree size. The resistance to ecan scab and other diseases on leaves, ecan scab on nuts and limb breakage were rated on a scale of 0 to 0 with 0 being the highest resistance. Nut weight, % kernel (kernel weight/total nut weight) and % os (nuts that were not filled) were eval uated on 00 nuts from each tree in 989. Results and Discussion A attern of alternate bearing occurred for ecan trees at the NFREC-Monticello (Table ). On average at least 50% of a cro was roduced in 989, 99, 99 and 996, whereas a maximum of only 6% of a full cro was roduced in 990, 99,99, and 995. For this eight year eriod an average of ca. % a full cro was roduced, (i.e. a full cro would equate to ca. 500 to 000 lbs. er acre). Thus, average yield for all cultivars combined was about 575 lbs/acre over this sev en year eriod; however, marketable yield was less than this as a result of losses due to nut diseases and insufficient kernel filling. Synchronous alternate bearing is believed to be the re sult of environmental and hysiological conditions. Only a small ercentage of ecan cultivars are adated to north Florida. Yield, nut quality, disease resistance and a ten dency to resist limb breakage are imortant criteria by which to determine the suitability of ecan cultivars to a given loca tion. Only 'Curtis' and 'Moreland' roduced an average of at least 50% of a full cro over an eight-year eriod. 'Cae Fear', 'Chickasaw', 'Curtis', 'GraZona', 'Kiowa', 'Melrose', 'Moreland' and 'Owens' roduced at least 0% of a cro. The best Proc. Fla. State Hort. Soc. 09: 996.

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4 Table 5. Resistance of ecan cultivars to limb breakage at the NFREC Monticello from Resistance to Limb Breakage' Cv Avg Cae Fear Cherokee Cheyenne Chickasaw Curtis Desirable Elliott GraBohls GraCross GraTex GraZona GraKing Griffin Jackson Kernodle Kiowa 6. Mahan Mahan Stuart Melrose Mohawk Moreland Owens Stuart Sumner Tejas Wichita Avg 'Resistance of limb breakage rated on a scale from 0 to 0. (0 = severe limb breakage, 0 = no limb breakage). the Indian-named cultivars had the least resistance to nut dis eases. The strength of wood varies greatly among cultivars (Ta ble 5). 'Cae Fear', 'Curtis', 'Elliott', 'Gra Tex', 'Griffin', 'Jackson', 'Moreland', 'Owens' and 'Tejas' were cultivars with the highest resistance to limb breakage. However, it must be remembered that limb breakage is both a function of inher ent wood strength and cro load. For examle, 'Tejas' does not fill nuts in north Florida even with a fungicide ro gram. Thus, wood of 'Tejas' does not have to contend with the weight of a heavy cro of nuts. Table 6 was comiled based uon data, observations, and discussions with research and extension ersonnel and grow ers. Six major arameters have been chosen as imortant vari ables: yield, nut size, % kernel, resistance to scab and other leaf diseases (downy sot, zonate leaf sot, vein sot, brown sot, leaf sot, liver sot, etc.), and recocity (the length of time required before a cro can be roduced = length of ju venility). Numerical yield and nut size ratings vary from (lowest) to (highest). Tree size has been taken into account in establishing yield ratings. Percent kernel, resistance to scab and resistance to leaf disease are rated from to excellent and recocity is indicated in years. 'Cae Fear' and 'Moreland' are cultivars highly recom mended for north Florida due to above average yield, nut size and disease resistance. Although nut size of 'Elliott' is small, it is highly recommended because of excellent disease resis tance. 'Curtis' is recommended because it has roduced con sistently high yields and is disease resistant. 'Sumner' is a recommended cultivar because it has a combination of yield, nut quality and disease resistance. 'Desirable' and 'Kio wa' are conditionally recommended because they require an intensive disease control rogram. 'Stuart' is conditionally recommended because of recocity and low ercentage kernel. 'Gloria Grande', 'Jackson', 'Kernodle', 'Melrose', and 'Owens' offer some otential (moderate to high yield, disease resistant) and are recommended only for trial since addition al information is needed. None of the remaining cultivars re leased from the U.S. Det. Agr. breeding rogram in Brownwood, Texas (denoted by Indian names) are recom mended for north Florida. Cultivars selected in the arid west are all suscetible to scab and other leaf diseases. 'GraBohls', 'GraCross', 'GraTex', and 'GraZona' do not aear in Table, and are not recommended. Sherman etal. (98) recommended 'Cae Fear', 'Choctaw', 'Curtis', 'Elliot', 'Kiowa' and 'Moreland' for trial in north central Florida. More recently, Crocker (988) recom mended 'Cae Fear', 'Curtis', 'Desirable', 'Elliot', 'Stuart' and 'Sumner' for commercial lantings in Georgia. While 'Cae Fear', 'Curtis' and 'Elliot' are recommended in the resent and in the two revious studies, 'Moreland' has not been adequately tested throughout the southeastern United States; however, under Florida conditions (i.e. high humidity and high disease ressures) it has erformed excetionally well. One final, very imortant consideration in selecting a e can cultivar is the attern of stigma recetivity and ollen shedding (Table 7). Pollen must be shed at a time when stig ma are recetive for ollination to occur. Since there is often little overla in stigma recetivity and ollen shedding within a given cultivar, cultivars with comlimentary ollination characteristics should be lanted together. 'Moreland', al though not listed in Table 7, is rotogynous and Cae Fear or Desirable can serve as ollenizers (O'Barr et al., 989). Proc. Fla. State Hort. Soc. 09:

5 Table 6. Yield, nut wt., i kernel, resistance to scab and leaf diseases, recocity and recommendation status of 7 ecan cultivars. Resistance to Scab" LeafDis.* Precocity* Recommendation + + Cultivar Yield' Nut wt.>» kernel Barton Caddo + Candy Cae Fear + Cheyenne + Chickasaw Cherokee Choctaw Curtis - Davis - Delmas + - Desirable +-- Elliott Farley Forkett - Gloria Grande - - Griffin Harris Suer Jackson - Kernodle - Kiowa - Mahan Mahan Stuart Melrose + - Moneymaker Moore + + Moreland + Owens + Schley Shawnee - Pawnee - Shoshoni + Stuart - - Success Sumner +-- Tejas -" Van Deman Wichita -" + excellent + + +? A R. -D ?? XTD INK XTD HR INK R CR HR R CR HR CR R Yield rating varies from (low), +(average), (), (excellent). >Nut wt. varies from (6.0 to 6.9 g), (7.0 to 7.9 g), ( to 8.9 g), (>9 g). x% kernel and resistance to scab and leaf diseases. "Precocity (in years to reach bearing age). ^Recommendation: HR (highly recommended), R (recommended), (recommended for trial), CR mended). "Variable. (conditionally recommended), (not recom- A summary of recommended cultivars will follow: Highly recommended cultivars 'Cae Fear': 'Cae Fear' trees are strong with a dee ta root. It is rotandrous and recocious. 'Cae Fear' has been a high roducer at the NFREC-Monticello. Nut weight is ty ically 7.5 to 8.g (58 nuts er ound) with a 55% kernel. Ker nel color is bright and quality is excellent. Resistance to scab is and resistance to other leaf diseases is fair. 'Elliott': The wood of 'Elliott' trees is also strong. It is rotogynous, but is not recocious. 'Elliott' has been a moderate roducer. Nut size is small, tyically 5.5g (8 nuts er ound) with a 5% kernel. Kernel color is bright and quality and fla vor are excellent. Resistance to scab and leaf diseases is rated although during the last several years there aears to be a decline in resistance. 'Moreland': 'Moreland' is a strong tree that has roduced consistently high yields in north Florida. It is rotogynous, but not recocious. Nut size is about 8.g (55 nuts er ound). The nut is similar to Schley. Percentage kernel is 55%. Color is somewhat bright and quality is high. Tolerance to scab and other leaf diseases ranks among the highest of any ecan cultivar. Recommended cultivars 'Curtis': 'Curtis' is a strong tree. It is rotogynous but is not recocious. It has been one of the most consistent ro ducers in north Florida, although nut size is small (5.0g, 90 nuts er ound). Percentage kernel is about 5%, and ker nels are somewhat dark in color with dark brown seckles. Flavor is. 'Curtis' is somewhat resistant to scab and other leaf diseases; however, because of small nut size, a dark kernel and late maturity, it is not highly recommended. 'Sumner': 'Sumner' is a largely overlooked ecan cultivar. It is a moderately strong tree and is moderately recocious. Nuts are large (g, 8 nuts er ound), and ercentage ker nel is about 5%. Overall nut quality is although kernels 8 Proc. Fla. State Hort. Soc. 09: 996.

6 Table 7. Stigma Recetivity and Pollen Shedding of Pecan Varieties at Brownwood, Texas, 97. Aril May Variety Desirable Caddo Cherokee Riverside Cae Fear Moore 8-5- (Major H Evers) San Saba Imroved Western Barton Cheyenne Mahan Chickasaw Candy Elliott Ideal Schley Aache Curtis Shoshoni Sioux Stuart Wichita GraBohls (Mahan x Odom) Mohawk Tejas Choc taw Shawnee Comanche Stigma Recetivity ^m^m Pollen Shedding can be somewhat dark. 'Sumner' has a high resistance to scab 'Desirable' is weak. 'Desirable' is rotandrous and is moderand other leaf diseases. ately recocious. Nut size is tyically large (g, 8 nuts er ound) with a 5% kernel. Kernel color is light and quality is Conditionally-recommended cultivars g od- Consumer accetance is very high. However, resistance to scab and leaf diseases is. A strict sray schedule (and 'Desirable':'Desirable'trees have been lanted extensive- weather) are rerequisites for successful culture in ly in the Southeast, often as a ollinizer to 'Stuart'. Wood of north Florida. Proc. Fla. State Hort. Soc. 09:

7 'Gloria Grande': 'Gloria Grande' is a strong tree and re sembles 'Stuart' in nut characteristics. It is rotogynous, but not recocious. Nut size is tyically large (g, 5 nuts er ound). Nut fill is better than 'Stuart', and is usually in the range of 5%. Kernel quality is and color is light. Resis tance to scab and other leaf diseases is very. 'Kiowa': 'Kiowa' trees are slow growing and the wood is brittle like many of the cultivars with Indian names. It is rot ogynous and recocious. Yields have not been high. The nut resembles 'Desirable' in aearance, although it is larger (log, 5 nuts er ound). Percentage kernel is about 55%. Color is light and quality is excellent. 'Kiowa' is very susceti ble to scab and other leaf diseases. 'Stuart': 'Stuart' is the best known ecan cultivar. Trees are moderately strong and do not require as much training or runing as other cultivars. 'Stuart' is rotogynous, but is not recocious. Nuts are large (9g, 50 nuts er ound) and attrac tive. Percentage kernel, however, is usually low (often 5%). Kernel color is average and quality is variable. 'Stuart' was for merly regarded as tolerant to scab and other leaf diseases, but is now rated as average in both categories. 'Stuart' retains a high status among ecan cultivars largely because of tradi tion. Cultivars recommended for trial 'Jackson': 'Jackson' was a oular cultivar back in the ear ly 900's. Tree growth habit can be somewhat willowy. Al though not recocious nor a heavy roducer nut size is large and kernel quality is high. It averages over log (0 nuts er ound) with a 5% kernel. Kernel color is light. 'Jackson' is moderately resistant to scab and leaf diseases. However, be cause it is not a high roducer, 'Jackson' is not recommended as a commercial cultivar. 'Kernodle': The wood of 'Kernodle' is considered strong. It has erformed well at the NFREC-Monticello. Nut size is large, (log, 5 nuts er ound) and quality is. 'Kerno dle' aears to be somewhat tolerant to scab and leaf diseases; however, because of limited information, it can only be rec ommended on a trial basis. 'Melrose': 'Melrose' is a strong tree and a consistent ro ducer of high yields. 'Melrose' is rotogynous, but is not re cocious. The ecan is medium in size (7.5g, 60 nuts er ound) and is somewhat ointed. Kernel color is medium dark. It has resistance to scab and other leaf diseases. 'Melrose' is only recommended on a trial basis for north Flor ida since little data are currently available. 'Owens': 'Owens' roduces a moderate cro of moderate to large sized nuts (u to log, 5 nuts er ound). It is rotandrous, but not recocious. Percentage kernel is about 5%. Color tends to be medium dark. 'Owens' has resistance to scab and leaf diseases. It is not recommended for commer cial lanting because of a dark kernel. Literature Cited. Andersen, P. C Performance of Pecan Cultivars at Agr. Res. Ed. Center-Monticello from 989 to 99. Proc. Southeastern Pecan Grow ers Assoc. 88:7-8.. Crocker, T. F Commercial Pecan Production in Georgia. Bull. 609, The Univ. of Georgia Coll. of Agr.. O'Barr, R. D., W. Sherman and W. A. Young Moreland: A Pecan for Louisiana and the Southeast. Cir. 9, Louisiana Agr. Ex. Sta.. Madden, G. D Potential varieties for the southeast through the U. S. Det. Agr. ecan breeding rogram. Proc. S. E. Pecan Grs. Assoc. 6: Madden, G. D. and E. D. Brown Here are methods to imrove ollination. Pecan Quart. 9(): Sherman, W. B., N. Gammon and R. H. Share. 98. Pecan Cultivar Evaluation in North Central Florida. Proc. Fla. State Hort. Soc. 95:-. 7. Wolstenholme, B. N. and H. L. Malstrom A Critical Araisal of Pecan Breeding Priorities and Prosects. Pecan Quart. Vol., No.. 0 Proc. Fla. State Hort. Soc. 09: 996.