Monte L. Nesbitt Texas A&M AgriLife Extension Service. Pecan varieties, pollination & spacing

Transcription

1 Monte L. Nesbitt Texas A&M AgriLife Extension Service Pecan varieties, pollination & spacing

2 High Sunlight must be maintained! Tree-to-tree shading causes. Reduced terminal shoot growth Reduced nut production More pronounced alternate bearing Smaller sized nuts Branch dieback Greater pest problems

3 Tree size and growth rate dictates spacing. 1-2 year old: Dia. 1.5 ft. 4-5 year old: Dia. 6-8 ft 7-8 year old: Dia ft year old: Dia. 20 ft

4 Ultimate Tree Size 70 ft spacing 40 Year Old Tree: Limb Spread Approx feet

5 Sunlight management plan 3 options u Plant at a permanent spacing that will not crowd. u 70+ ft? u Gives up some early production income. u Tree Removal: Cut down trees or move trees to another site with a tree spade u Hedge Prune: Annual practice to cut back limbs and increase light interception.

6 TREE SPACING High Density Recreational Orchard First Planting 47 X X X X Trees /Acre Trees/ Acre Commercial Orchard First Thinning 20 x X X X X X Trees /Acre 40 x X x X 60 12

7 Hypothetical comparison of initial tree density using precocious cultivar (Cape Fear) 70 x x x x x x x 33 Years 1-9 Years Years Years x x ,000 20,000 30,000 40,000 50,000 Yield (lbs/ac)

8 Temporary Cultivars; precocious, heavy producing trees that need to be planted in tree removal positions to get the most from those positions in the orchard. Creek Kiowa Cape Fear Shoshoni Navaho Wichita Permanent Cultivars; Varieties with sound traits through maturity. Desirable Forkert Elliott Nacono Sioux Caddo Wichita Western

9 Orchard Design Patterns Square 35 x 35 (35 tpa) Rectangle 30 x 60 (24 tpa) T T T T T T T T

10 The Alternative to Tree Removal Pawnee

11 Texas pecan-growing regions

12 If starting over in the East region, surveyed Texas growers would plant 10 Farms Repor-ng % of growers who would replant variety Desirable (I) 50 Cheyenne (I) 50 Nacono (II) 30 Pawnee (I) 30 Kiowa (II) 20 Prilop 20 Navaho (I) 10 Choctaw (II) 10 Sioux (II) 10 Wichita (II) 10 Desirable 43 nuts/lb 52% kern. Cheyenne 48 nuts/lb 58% kern.

13 If starting over in the Central region, surveyed Texas growers would plant 9 Farms Repor-ng % of growers who would replant variety Pawnee 55.6 Wichita 55.6 Desirable 22.2 Cheyenne 22.2 Kiowa 11.1 Kanza 11.1 Choctaw 11.1 Lakota 11.1 Pawnee 44 nuts/lb 58% kern. Wichita 43 nuts/lb 62% kern.

14 If starting over in the West region, surveyed Texas growers would plant 4 Farms Reporting % of growers who would replant variety Western 100 Wichita 100 Mandan 50 Pawnee 25 Cheyenne nuts/lb 58% kern. kern. If it s not broke, don t fix it! Wichita 43 nuts/lb 62% kern.

15 Texas A&M Orchard Scab Evaluation-2016 Desirable Nacono Kanza Lakota Cultivar Lakota Kanza Eclipse Oconee Caddo Lipan Waco Wonder Sioux Excel Apalachee Mandan Choctaw Waco Nacono Pawnee Minimum Maximum Average

16 Pecan Pollination Type I Type II Catkins first Nutlets First April 20 April 30 May 10 May 20 Pawnee (1) Western (1) Wichita (II) Nacono (II) Brownwood, Tx Flower Receptivity=Red Pollen Shed=Yellow **Chart: Tommy Thompson

17 Is Self Pollination OK? Fruit drop days after pollination is likely due to no pollination or possibly self-pollination (second drop period). Subtle drops days after pollination may also be due to self-pollination Some varieties tolerate self-pollination better than others. Xenia effect has been published, noting depression of fruit-related traits caused by self-pollination.

18 Low humidity and high temperature accelerate catkin development and pollen shed Damp weather prolongs the pollen shedding period.

19 Pistillate flower receptivity is also affected by weather (humidity, temp., wind). Color is not always a reliable indicator of receptivity, but rather tackiness/dampness. The earlier that flowers receive pollen after receptive, the better (1 day > 4 days).

20 One catkin has three stalks One stalk= flowers One flower=3-5 anthers 1 Anther=2,000 pollen grains. Pollen potential One catkin=3 stalks x 110 flowers x 4 anthers x 2,000 pollen grains= 2,640,000 pollen grains

21 How far can pecan pollen travel? Some say that pecan pollen is relatively large and thus doesn t fly far. Others believe it may travel significant distance (2 miles). A practical distance of 150 feet is commonly recommended. Wood (2000) reported highest crop set where pollenizer tree was adjacent to and not more that two trees from target tree. A 4-row/1-row orchard layout has been proposed. Alternating rows might be even better.

22 Contact Information (979) Texas Pecan Shortcourse: January 25-28, 2018 (4-Day Format) Texas A&M Pecan Orchard & HortTREC