10 



BULLETIN 1320, U. S. DEPARTMENT OP AGRICULTURE 



of the April 19 planting, 11.2 nodes on the April 28 planting, 10.7 

 nodes on the May 5 planting, and 13 nodes on the May 12 planting. 

 In order to show the number of nodes on plants in the different 

 plantings on the same dates, the weekly records of nodal develop- 

 ment are graphically presented in Figure 3. These curves show that 

 the nodal development of the first three plantings was nearly parallel 

 throughout the period following the appearance of squares until 

 August 11. The May 12 planting, however, produced nodes more 

 rapidly throughout this period. From June 1 until August 11, a 

 period of 71 days, the April 19 planting produced 13.1 nodes. From 

 June 8 until August 11, a period of 64 days, the April 28 and May 5 

 plantings produced 1.1,1 and 11 nodes, respectively. From June 15 

 to August 11, a period of 57 days, the May 12 planting produced 13 

 nodes. The average number of days per node for each planting was 

 5.42, 5. 77, 5.82, and 4.38 days, respectively. 



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Fig. 3. — Average number of nodes on the main stalks of cotton plants at weekly intervals following 

 the appearance of squares at San Antonio, Tex. 



Each node produced on the main stalk after the beginning of the 

 fruiting stage of the plants represents the formation of a fruiting 

 branch. Thus, the May 12 planting produced the same number of 

 fruiting branches in 15 days less time than was required by the April 

 19 planting. 



Figure 4 gives the average height of 10 plants in each planting at 

 weekly intervals from June 1 until August 11. While the height of 

 plants is a factor of less importance than the nodal development, 

 it will be of interest as showing the relative size of plants in each 

 planting. The more vigorous growth of plants in the later plantings 

 is shown in these curves. On July 13 the plants of the May 12 plant- 

 ing were the largest, with the May 5, April 28, and April 19 plantings 

 following in the order named. Although the plants in the April 19 

 planting maintained a larger number of nodes throughout the season, 

 after the middle of July they were the smallest. The difference in 

 the size of representative plants in each planting is shown in Plates 

 I and II. 



This tendency toward the development of larger plants in later 

 plantings is to be expected, especially on the heavier types of Texas 



