Variability of Protoplast‐derived Potato Clones¹

Abstract

Sixty‐five selected clones of potato (Solanum tuberosum cv. Russet Burbank) regenerated from mesophyll protoplasts (protoclones) were analyzed for variability under field conditions. Protoclones were planted in randomized complete blocks replicated six times. During the growing season and after harvest a total of 35 characters were measured for each clone and compared with similar measurements from the parental ‘Russet Burbank’ and with another virus‐tested clone of the cultivar. Statistically significant variation was found for 22 characters, variation not amenable to statistical treatment in 4 characters, and no variation in 9 characters. Protoclones were nearly equivalent in most characters to both Russet Burbank standards. However, quantitative data showed that each protoclone differed from Russet Burbank in some trait(s). Variation ranged from a minimum of one character in three protoclones to a maximum of 17 characters in one protoclone. Differences in vine morphology, tuber yield and composition, maturity and flowering were observed. Some of the variability found should be an improvement over normal traits found in the normal cultivar. Further testing is necessary to determine both the stability of and the effect of the environment on this variability. However, the data do suggest that for potatoes, protoplast regeneration may offer a new means of generating variability of potential use for crop improvement.

Phenotypic variation in plants regenerated from protoplasts: The potato system

“…None of the clones, however, were invariant. 24 Of the 63 clones, several have been selected for continued field examination as well as for determination of tuber quality characteristics. Several thousand more clones have also entered field trials with additional results coming in each year.…”

Field performance of transgenic potatoes

“…Such changes are well known among plants regenerated from cell culture (Evans 1989;Karp 1991), and have been frequently observed under field conditions in potatoes (e.g., Shepard et al 1980;Secor & Shepard 1981;Potter & Jones 1991). They are not expected in the control parental lines in these field trials, since the plants originated from intact shoot cultures and were never regenerated from disorganised cell cultures (Potter & Jones 1991).…”

Induced Mutations In Vegetatively Propagated Crops

“…Most cited is the work of Shepard and colleagues, who found variation for resistance to late blight (Phytophtora infestans) and early blight (Alternaria solani) in the cultivar 'Russet Burbank' (Shepard 1981;Secor and Shepard 1981;Shepard et al 1980). Despite optimistic reports, new somaclonally derived potato cultivars have not been commercialized yet.…”