VARIATIONS IN PECANS 



F. W. Brtson 

 A. and M. College, College Station. Texas. 



FEW plants show such a wide 

 variabiHty as the pecan when it 

 is reproduced from seed. This 

 is so great as effectually to prevent 

 the propagation of improved varieties 

 by seed, though it offers the pecan 

 grower a good opportunity for the intro- 

 duction of new varieties by selection. 

 New varieties obtained can be perpet- 

 uated indefinitely by budding and graft- 

 ing. From the breeder's point of view 

 this great diversity of the sexual pro- 

 geny of pecan trees is very fortunate, 

 as it is only through the occurrence of 

 variations in any plant that further im- 

 provement within that species is pos- 

 sible. 



The Pecan Crop 



Every section of the country has a 

 crop or enterprise of which it is proud. 

 The time is probably not very remote 

 vv^hen the South will boast as loudly 

 of her pecan industry as she does now 

 of her cotton, and pecans will be as 

 widely advertised as the walnuts of 

 California. The pecan is indigenous 

 only to certain parts of the southern 

 United States and a small section of 

 northern Mexico. Dean Kyle, of the 

 Texas A. and M. College, declares that 

 Texas is the real home of the pecan ; 

 and Texas alone has more native pecans 

 than all the other states combined. 



In 1919. 16.755,421 pounds of pecans 

 valued at $3,698,233 were produced in 

 Texas. Probably nowhere else in the 

 world does nature, unaided by man, 

 produce a crop, ready for the market, 

 of as great a money value. Within the 

 last twenty years large areas have been 

 planted to improved varieties of pecans 

 in Georgia, Alabama, Mississippi, Flor- 

 ida, and Louisiana ; and these states 

 are now leading in the production of 

 improved varieties. 



The pecan is monoecious, the stam- 

 inate flowers or catkins being borne 

 on wood of the preceding season's 

 growth, while the pistillate flowers are 

 borne on wood of the current season's 

 growth. The pollen grains are carried 

 from the catkins to the pistils by wind 

 primarily, and by gravity. Naturally, 

 then, a high percentage of cross polli- 

 nation will take place. It is believed 

 that under the most favorable climatic 

 conditions, viable pollen grains may be 

 carried a distance of three or four 

 miles. The pecans produced by one 

 tree are the result of the union of the 

 sperm cells of pollen grains from many 

 different trees with the egg cells of the 

 mother tree. Consequently the result of 

 each fertilization is apt to vary in one 

 or more respects from the result of 

 all other fertilizations, owing partially 

 to the difference in the paternal in- 

 fluence as well as to the difference due 

 to segregation of characters in the 

 production of the egg cells by the 

 mother tree. The shell of a pecan is 

 purely maternal tissue, and so similar 

 are all the nuts produced by a variety 

 that trees, the variety name of which 

 is not known, can be identified by the 

 nuts they bear. 



Production of New Varieties 



Self- or close-pollination of pecans 

 for seed purposes is frequently recom- 

 mended. It is no doubt a good practice 

 but it does not insure an exact repro-__ 

 duction of the pecans planted because 

 of the heterozygous character of the 

 pecan ; it only increases the chances 

 of getting a good tree from the seed 

 planted. The pecan tree is slow in 

 coming into bearing, requiring from 

 five to twelve years from the time a nut 

 is planted until the tree produced from 

 it bears seed. Any attempt to produce 



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