THE CONTROL OF COTTON WILT AND EOOT-KNOT. 15 



Planting. — TJie individual selections should be jJanted by hand 

 in these progeny rows. A small bull-tongue or wooden V attached 

 to a plowstock may be used to open a shallow trench in the beds. 

 The seeds are dropped in this trench at the proper intervals and 

 covered about an inch deep with the foot and the soil is very slightly 

 compacted. Four or five seeds to the hill should be used and the 

 remahider saved for ])0ssible rejdanting. Eacli row should be marked 

 by a stake at the end, l)earing the number of tlie individual selection. 

 This should be driven down so that the AvhilHetrees will not liit it 

 during cultivation. Stakes should be at least ^ by 2^ by 18 inches 

 long and planed on one side so that the numbers can be written on 

 them \nth a heavy pencil. For convenience in field labeling and in 

 keeping breeding records, each selection grown by. an individual 

 farmer is given a number, as 1, 2, etc.; and each individual selection 

 made from these has another number added to tlie first witli a dash 

 between, as 2-1, 2-2. 



Thinning, wilt counts, and roguing. — All progeny rows should be 

 gone over about the middle or last of May, the exact time depending 

 on the date of planting, and all hills thinned to one plant, leaving the 

 healtldest plants. A record of the number of hills should be made 

 to form a basis for the determination of wilt resistance. Counts of 

 the \\dlted plants in each row should be made about June 20, August 

 1, and September 15. The total number of wilted plants compared 

 witli the figures of the original stand will give the percentage of 

 wilted j)lants. Wilt resistance should be the first and most impor- 

 tant consideration in the selection of the best progeny rows, only 

 those being taken which are highly resistant. After each wilt count 

 the diseased plants should be pulled or rogued out to prevent their 

 crossing on other plants or being picked by mistake with the healthy 

 plants. 



The year following, when an increase plat is grown from the 

 progeny-row seed, a similar method of roguing, involving the pulhng 

 out of all wilted and nontypicalplants, is practiced to maintain the 

 purity and wilt resistance of the strain. 



Selection and note taking. — After the last wilt counts in September 

 have been made, the progeny plat should be gone over carefully and 

 all rows discarded that show mucli wilt. Records should be matie 

 of the principal characters of the jirogeny rows, such as earliness, 

 uniformity, size, etc., on note l)lanks j)rovided by the Department 

 of Agriculture. In the books in which these blanks are bound, 

 detailed directions for taking notes are printed and the time required 

 for the work is very largely reckiccd by the use of a series of symbols 

 to indicate the degrees of the characters present which are listed on 

 the note blanks. 



[Clr. OU] 



