sou STATE BOARD OF AGRICULTURE. 



SELFING. 



S 



Selfing is an artificial method of causing naturally allogamous plants 

 to self-fertilize. This method results in what naturally occurs in the case 

 of autogamous plants. Selfing allows homoz3'gotes to appear and to 

 be isolated. In corn the method consists in bagging both ear and tassel 

 before the silks appear and before the pollen shatters. When the silkf 

 are ready, the pollen collected from the tassel is used to pollinate the 

 silks on the same stalk. 



SYSTEMATIC STUDIES IN INHERITANCE. 



In making crosses, it often happens that characters are involved that 

 are not familiar to the experimenter. In order to proceed intelligently 

 it is necessary to make extensive statistics on the populations resulting 

 from the generations following the cross, and to make the calcula- 

 tions necessary to determine the relation of certain characters correlated, 

 allelomorphic, or independent. If allelomorphic (alternative) which 

 character is dominant, and how many independent factors are involved in 

 the gap between the two characters. 



These questions may be answered by means of the following considera- 

 tion : 



a. Correlated characters are always found together in the same plant . 



b. Dominance can usually be told by the appearance of the first filial 

 generation. The dominant character is normally found in three times 

 as many plants (in the second fiHal generation) as those that_express the 

 recessive character. 



* c. A pair of allelomorphic characters generate a single genoplex, 

 and are probably represented by a single pair of chromosomes. 



d. Independent characters generate at least two genoplexes, and 

 must be represented by different pairs of chromosomes. 



RATE OF SEEDING. 



In the case of new varieties the grower should know the rate best suited 

 for the planting. Varieties vary greatly in stooling power. The size of seed 

 produces varying numbers of seed in a given weight and measure. This 

 increases the need for experimental tests. 



DATE OF SEEDING. 



As crops and certain varieties also vary greatly in the way they adapt 

 themselves to a season, investigations on date of seeding are as important 

 as the rate of seeding. 



