Characteristics | Management Profile | Strains | Tables
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National Trial Performance The Russet Norkotah strains were first entered in the Western Regional Potato Variety Trials in 1996. The two strains entered were TX #112 and TX #278, and were tested at nine locations. Except at Othello, WA, the two strains out-yielded the standard Russet Norkotah. The mean yield of US#1 for Russet Norkotah over the nine sites was 316 cwt/a while TX #112 yielded 401 cwt/a and TX #278 yielded 381 cwt/a. In 1997 and 1998, strains CO #3, CO #8, and TX #223 were added to the previous two strains tested. Figure 2 shows total yield of these five strains compared to the standard averaged over nine late-harvest sites and two years, 18 site-years. Strain CO #3 gave the significantly highest yield in these trials, but there was no significant difference between the other strains, CO #8, TX #112, TX #223, and TX #278. The total yield of all were higher than the standard Russet Norkotah. In 1999 and 2000, two new Texas strains, TX #102 and TX #296, were tested against the standard. They both yielded higher than the standard at all sites. The mean yield of US#1 for Russet Norkotah over the nine sites and two years were 322 cwt/a, while for TX #102 and #296, they were 391 and 395 cwt/a, respectively. In all the Western Regional Trials, all strains were rated higher for the fresh market than the standard Russet Norkotah. |
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Performance in Nebraska In early trials in Nebraska, just the two Colorado strains, #3 and #8, were tested. However, in the Nebraska trials of 1999, 2000 and 2001, the two Colorado strains were tested along side the five Texas strains -- #102, #112, #223, #278, and #296. These trials were conducted at three locations in the State -- O’Neill in the north east, Imperial in the southwest and Scottsbluff in the Panhandle. Nitrogen fertilization was above recommendation for Russet Norkotah at O’Neill (Table 2) while, at Imperial and Scottsbluff, it was at or slightly below recommendation. The highest yields were consistently obtained from O’Neill and the lowest at Scottsbluff (Table 2). Percent of total that are US grade A was at Scottsbluff which also had the greatest percent of mis-shaped tubers. Specific gravity was highest at O’Neill and Scottsbluff. Maturity observations of these strains at Scottsbluff over the three years indicate that CO #3 has the longest maturity, about two weeks later than the standard. The next longest maturity was shown by TX #112. With about a week longer maturity than the standard are CO #8 and TX #223. The strains TX #102, TX #278 and TX #296 have about a three-day longer maturation. The yields of tubers greater than 1.88 inches are summarized according to location averaged over three years in Table 3. All strains except TX #102 yielded significantly greater than the standard and were not significantly different from each other (Figure 3). When noting the sites when a strain yields significantly more than the standard, one finds that only TX #278 consistently did so at all three sites averaged over the three years. The two Colorado strains and TX #223 yielded significantly more at two of the three sites. Figures 4, 5 and 6 show the percent total yield of tubers > 1.88 inch, percent of tubers that are mis-shaped, and the specific gravities of the strains, respectively, averaged over three sites and three years, nine site-years. With the exception of TX #223, all the strains produced a higher percentage of tubers greater than 1.88 inch (Fig. 4). Significantly higher percentage of mis-shaped tubers was obtained with CO #3, TX #223 and TX #296 (Fig. 5). CO #3 and TX #296 had a greater specific gravity than the standard (Fig. 6). Overall, TX #278 seems to show the best performance of the strains so far in Nebraska but most of them perform similarly. TX #102 does not show promise. The tendency to mis-shape of CO #3, TX #223 and TX #296 is a caution. |
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