BUEEAU OP PLANT INDUSTRY. 149 



three seasons' work to combine into a uniform strain the sweet seeds 

 and prolific habit of sweet corn with the long harsh husks of south- 

 ern varieties of field corn, thus producing a vai'iety of sweet corn 

 as resistant to the corn worms as the southern varieties of field corn. 

 Studies of thirty different varieties of corn grown by the American 

 Indians have demonstrated that in these varieties there are many 

 adaptations, the value of which seems to have been overlooked. The 

 Assiniboine and Mandan Tribes have both sweet and field varieties 

 that surpass commercial varieties in earliness. Others, ^particularly 

 the Omaha and Otoe Tribes, have varieties showing a remarkable 

 development of slender leafy stalks suitable for forage. It is planned 

 to continue the study of these and other Indian varieties with a view 

 to providing breeding material for the improvement of commercial 

 strains. The drought-resistant qualities of Chinese waxy corn have 

 been repeatedly demonstrated and the possibility of developing use- 

 ful hybrid varieties is being investigated, but the direct use of this 

 type of corn for purposes of crop production has seemed to be ex- 

 cluded by the small yield of the individual plant. Experiments at 

 San Antonio, Tex., have shown that satisfactory yields can be secured 

 by closer spacing and that ears are regularly produced when the 

 plants stand only two inches apart. 



Date offshoot propagation. — The investigations on the rapid 

 propagation of date offshoots at the Government date garden, Indio, 

 Cal., have proved that warmth and humidity are great aids in root- 

 ing date offshoots. It has also been found that cold frames without 

 artificial heat, made by putting canvas frames over the offshoots in 

 the field, aid in forcing a rapid and healthy growth. The majority of 

 the offshoots imported by private growers in the Imperial and 

 Coachella Valleys are being rooted in the field by the use of this cold- 

 frame method. 



Canker-resistant citrous fruits. — A trip was made to Japan, 

 China, and other oriental countries to determine the possi^Dility of se- 

 curing citrous fruits resistant to citrus canker (caused by Pseudomo- 

 nas citri) , a disease which has resulted in great damage to grapefruit 

 plantations in Florida. This disease was found to be widely spread 

 in southern Japan, southern China, and the Philippine Islands, and 

 as no attempt at eradication had been made in these countries it 

 was possible to secure valuable data relative to the comparative 

 canker resistance of different varieties. It was found that the 

 pomelos (commonly called Buntan in Japan) were decidedly re- 

 sistant to canker, some of the varieties examined having suffered no 

 appreciable damage from the attacks of this disease. In view of 

 the fine quality of many of these pomelos, which are similar to the 

 shaddocks of Florida and the West Indies, it is believed that hybrids 

 between them and the ordinary grapefruit can be secured which will 

 possess the resistance to canker shown by the Buntan, while retaining 

 the desirable characteristics of the grapefruit. Through a new 

 method for the long-distance shipment of pollen, developed in con- 

 nection with the investigations of the past year, grapefruit pollen 

 was sent from Florida to Japan and used successfully in making 

 crosses between the grapefruit and selected varieties of the Japanese 

 pomelo. 



