scholarly journals Physiological and Morphological Studies on Potato Plants : Part 18. On the influences of nature and of age of seed tubers on some physiological behaviors at the time of sproutiong of the tubers

1955 ◽  
Vol 23 (4) ◽  
pp. 249-250 ◽  
Author(s):  
Takashi TAGAWA ◽  
Yozo OKAZAWA
Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 659-665 ◽  
Author(s):  
D. C. Henne ◽  
F. Workneh ◽  
A. Wen ◽  
J. A. Price ◽  
J. S. Pasche ◽  
...  

An emerging disease of potato in the United States, known as “Zebra Chip” or “Zebra Complex” (ZC), is increasing in scope and threatens to spread further. Here, we report on studies performed to understand the role of tuberborne ZC in the epidemiology of this disease. Depending on variety, up to 44% of ZC-affected seed tubers (ZCST) were viable, producing hair sprouts and weak plants. Chip discoloration in progeny tubers of ZCST was more severe than those from ZC-asymptomatic seed tubers but varied depending on whether progeny tubers or foliage were positive or negative for ‘Candidatus Liberibacter solanacearum’. A low percentage of greenhouse-grown plants produced by ZCST tested positive for ‘Ca. Liberibacter’. No adult potato psyllids became infective after feeding upon these plants but they did acquire ‘Ca. Liberibacter’ from field-grown plants produced by ZCST. Plants with new ZC infections near plants produced by ZCST were not significantly different from healthy plants, whereas plants affected with ZC from infectious potato psyllids had significantly more ZC infections near either plants produced by ZCST or healthy plants. We conclude that, in areas where ZC is currently established, plants produced by ZCST do not significantly contribute to ZC incidence and spread within potato fields.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 486f-486
Author(s):  
James A. Okeyo ◽  
Ronald D. Morse

Seed tubers of `Yukon Gold' (Solanum tuberosum L.) exhibit strong apical dominance, resulting in relatively poor stem emergence. Cutting seed tubers to overcome apical dominance in `Yukon Gold' results in irregular, uneven stem emergence. In 1992 and 1993, experiments were conducted to evaluate the effects of dehaulming (excising stems to ground level after field emergence) whole, cross- and longitudinal-cut seed tubers of `Yukon Gold' on canopy growth and tuber yield. For all seed piece types, dehaulming during the first week of field emergence produced uniform plant stands and increased yields of U.S. no. 1 tubers by 16 and 42% and large tubers (> 6.4 cm dia.) by 340 and 64% in 1992 and 1993, respectively. Our data indicate that tuber bulking rate was increased by dehaulming. The possible causes and implications of increased tuber bulking rates in dehaulmed potato plants are discussed.


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