LIGHT 77 



sixty-two bushels of oats per acre from large seed and only forty- 

 seven bushels from small seed. Both the small and large seed were 

 selected from the same stock each year. 



Disease Resistance. — The Wisconsin Station has developed a 

 variety of cabbage resistant to the disease of ^^ellows^' (Fig. 165). 

 Much work has already been done by investigators in developing 

 disease-resistant plants. 



Seed Improvement. — The Cornell Station of New York has 

 demonstrated a yield of 3.57 tons of timothy hay per acre with 

 improved varieties as compared with 2.04 tons with ordinary 

 timothy. The test was made on the same kind of soil and with seed 

 of equally high germination test. This is a seventy-five per cent 

 increase in favor of improved varieties. The quality of hay was 

 also much better. 



As a result of working on the increase and decrease in protein 

 and oil content of corn, the Illinois Station developed from a single 

 variety of corn in ten years' time, one strain contaming 65 per cent 

 more protein than another, and a third strain containing 177 per 

 cent more oil than a foiu-th strain. 



These are but a few of many examples illustrating the possi- 

 bilities of good seed and the advancements that are being made in 

 improving varieties. 



Favorable Temperature. — The temperature at which plants 

 make their best growth varies with different farm crops. In 

 diversified farming there is no weather but what is good weather, 

 since when it is unfavorable for one or two crops it is favorable 

 for the others. A hot sun, though favorable for corn, often causes 

 injiu-y to the Irish potato in '^ burning" the leaves (sun-scald). 

 Cool and moist weather during the fore part of a growing season 

 is favorable for grains, but unfavorable for corn. Our poor corn 

 years are usually the result of cold, wet weather during the summer 

 and fall months. Excessive heat and much dampness generally 

 cause much damage to grains in favoring the development of leaf 

 and stem rusts. 



Since weather is beyond the control of man, except under 

 artificial conditions, the best that a farmer can do is to plant his 

 seed at such time as to enable the respective crops to take advan- 

 tage of the favorable temperature conditions. In this the farmer 

 is guided in his activities largely by the average weather of his 

 section or locaUty (Chapter V). 



Light. — In Chapter V we learned that sunlight is necessary for 



