ABSTRACTS 



Authors of scientific papers ar^ requested to see that abstracts, preferably pre- 

 pared and signed by themselves, are forwarded promptly to the editors. The 

 abstracts should conform in length and general style to those appearing in this issue. 



BOTANY. — ^.4 teosinte-maize hybrid. G. N. Collins and J. H. Kempton. 

 Journ. Agric. Research. 19: 1-37. Pis. 7, figs. 33. 1920. 



The diminutive variety of pop corn known as Tom thumb was crossed with 

 the teosinte of Florida {Euchlaena mexicana Schrad.), using teosinte as the 

 female parent. Eleven hybrid seeds were obtained and six plants were raised 

 to maturity. The first generation plants were intermediate between maize 

 and teosinte. The pistillate inflorescences were all four-rowed and the 

 staminate inflorescences resembled those of maize in that they terminated 

 in eight-rowed central spikes. 



A population of 127 second generation plants was raised from the seed 

 of a single self-pollinated first generation plant. These plants like those of 

 the first generation were intermediate between maize and teosinte but with 

 greatly extended range of variation. Thirty-three of the characters that 

 differentiated the parents were studied and with one or two exceptions no 

 evidence of alternative or Mendelian inheritance was found. 



With respect to the individual characters, the extreme variants approached 

 or even exceeded those of the parents but none of the plants possessed any 

 very large number of the characters of either maize or teosinte. All com- 

 binations of characters appeared that might be expected with so limited a 

 number of individuals. There were many instances of coherences or partial 

 couplings but there was an almost equal number of instances where char- 

 acters derived from different parents showed a tendency to combine more 

 ftequently than would be expected as the result of chance. This phenom- 

 enon is termed "disherence." 



While there appeared to be no imcompatible combinations, there were 

 on the other hand no completely independent characters. A surprisingly 

 large number of the plants combined the abundant production of suckers, 

 characteiistic of the teosinte parent, with the sturdy upright character of 

 maize and resulted in very leafy compact plants of a type that should prove 

 valuable for forage purposes. It remains to be seen whether the new com- 

 binations can be maintained and made to breed true. J. H. K. 



BOTANY. — Daily development of kernels of Hannchen barley from flowering to 



mattirity. Harry V. Harlan. Journ. Agric. Research 19: 393-429. Pis. 



9, figs. 17. 1920. 



The growth of barley kernels is traced from flowering to maturity. By 



an accurate method of sampling, growth in periods as short as twelve hours 



has been recorded. Length, lateral diameter, dorso-ventral diameter and 



weight are all shown to be measurable. The length growth of barley kernels 



is much more rapid than had been supposed. The full length is reached by 



the seventh day after flowering. As soon as the length growth is checked 



a rapid gain in dry matter begins, accompanied by increase in the lateral and 



dorso-ventral diameteis. The indices of growth have proved very valuable 



in measuring the reactions to water supply and other factors in nutrition. 



H. V. H. 

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