[ti:With Resistant Crops, Progress Can Raise New Problems] [ar:Bob Doughty] [al:Agriculture Report] [by:www.51voa.com] [00:00.00]This is the VOA Special English [00:03.07]Agriculture Report. [00:04.81]Plant breeders and genetic engineers [00:08.73]keep working to give crops the strength [00:11.53]to resist threats like insects, [00:14.33]diseases, droughts or floods. [00:17.00]But before you can resist a threat, [00:20.67]you need to understand it. [00:22.91]We told you last week [00:25.46]about a newly completed [00:27.64]genetic map of the organism [00:30.50]that causes late blight. [00:32.61]That disease led to starvation [00:35.91]in Ireland from potato shortages [00:38.96]in the middle of the eighteen hundreds. [00:41.88]The new genome could lead to [00:44.49]better ways to protect potatoes, [00:47.45]tomatoes and other crops. [00:49.81]Science may supply a stronger crop. [00:53.92]Yet that does not always guarantee demand. [00:58.40]Nik Grunwald from the United States [01:01.76]Agriculture Department worked [01:04.43]on the international team [01:06.25]that completed the genome. [01:08.43]He says it is possible to grow potatoes [01:12.28]that resist late blight. [01:14.59]But these may not look like Russet potatoes. [01:19.13]And most American farmers [01:21.68]grow Russets because, [01:24.19]as Nik Grunwald puts it, [01:27.52]"that is where the demand is." [01:29.95]Another example of scientific progress [01:33.99]involves a natural bacterium known as Bt. [01:39.16]Bt is used as a pesticide [01:43.14]to fight cotton bollworms, [01:46.31]corn borers and other pests. [01:49.05]Scientists have found a way [01:51.97]to grow cotton plants [01:54.02]that contain a Bt gene, [01:56.95]reducing the need for pesticides. [01:59.81]But sometimes, [02:01.49]when one problem gets solved, [02:03.91]another one appears. [02:06.15]In China, some farmers [02:09.26]and researchers blame a decrease [02:11.94]in pesticide use for an increase [02:15.36]in pests unaffected by Bt. [02:18.41]Also, there are concerns [02:21.33]that some organisms could begin [02:24.25]to resist the plants designed to resist them. [02:28.48]And scientists are reporting this week [02:31.90]on what they call the "indirect costs" [02:36.07]of a virus-resistance gene in Cucurbita. [02:40.74]This is the species of squash [02:43.66]that includes pumpkins and gourds. [02:46.58]The scientists say virus-resistant [02:50.81]transgenic squash are grown throughout [02:53.80]the United States and much of Mexico. [02:56.60]The genetically engineered squash [03:00.27]are usually larger and healthier than wild squash. [03:04.37]But a three-year study showed [03:07.67]that beetles like to feed more [03:10.10]on the transgenic plants, [03:12.21]increasing cases of wilt disease. [03:15.20]The report by a team from the United States [03:19.18]and China appears in the Proceedings [03:22.79]of the National Academy of Sciences. [03:25.52]The researchers point out that gene flow [03:29.57]between crops and their wild relatives [03:32.43]is common and difficult to contain. [03:35.60]They note concerns that wild plants could, [03:39.83]as a result, [03:41.39]gain genetically engineered resistances. [03:44.75]And these could affect the [03:46.67]natural balance in their environment. [03:49.85]And that's the VOA Special English [03:53.45]Agriculture Report, [03:55.01]written by Jerilyn Watson. [03:57.43]I'm Bob Doughty.