Determination of Reliable Selection Criterias for Early Generations in Potato Breedıng

 Determination of Reliable Selection Criterias for Early Generations in Potato Breedıng

Mete Kaan BÜLBÜL

ABSTRACT

              This study was conducted to evaluate the effectiveness of some visual selection criteria; and, to determine the reliable selection criteria for seedling and the first clonal generations in potato breeding programs aiming to develop of high yielding cultivars.

              The hybrid true potato seeds from eleven crossing combinations were obtained with crossing in Nevsehir during summer season in 2010. The seedlings from true seeds were grown in greenhouse in Hatay from December 2010 to March 2011 to obtain seedling generations. Then, one tuber of each seedling was planted into field in Kayseri in June 2011 to obtain the first clonal generation. In each generation, some morphological and agronomic traits, which can be used as selection criteria, were measured on each plant. A Breeder Preference Score (BPS) on 1-9 scale (1 the worst-9 the best) were also given to each plant based on their visual appearance before and after harvest. Then, the correlation coefficients were calculated between measured traits and given BPS in each generation. The correlation coefficients between BPS of seedling and the first clonal generation for each hybrid plant were also calculated.   

                 The results indicated that morphological characteristics of same plant could significantly vary between seedling and field generations. The selections for even tuber shape and eye depth may be misleading when the tuber size is very small in the seedling stage. It was concluded that the threshold level for BPS should be lower in the seedling stage due to weak correlation between BPS values of seedling and field generations.                                                                                                       

 Objectives

This study was conducted;

üto evaluate the effectiveness of some visual selection criteria; and,

üto determine the reliable selection criteria for seedling and the first clonal generations in potato breeding programs aiming to develop of high yielding cultivars.

Methods 

üThe measurements were done on 40 plants in each of 10 cross combinations.

üThe experiment for seedling generations were conducted in greenhouse at the Mustafa Kemal University in Hatay, Turkey between November 2010 and March 2011.  

üThe field experiment or the first field generation were conducted in the seed production site of Doga Seed Inc. İn the Tomarza, Kayseri, Turkey between June-October 2011.

üThe following morphological and agricultural traits were evaluated in both experiments: The seedling/plant height, stem diameter, width and length of terminal leaflet, tuber shape, eye depth, skin appearence, skin color, number of tubers per plant and tuber weight per plant.

üBreeding Preference Score (BPS) (1 very bad-9 very good) according to general appearance of haulms (BPSHw) and tubers (BPSTbr) were given to each plant.

Figure 1. Cross combinations used in the study.

Combinations	Number of Genotype of Seedling		Number of Genotype of First Clonal Genaration
	Planted in theNumber of TPS	Number of Tubers of Seedling Generation	Number of Single Tuber Planted	Number of Tubers of First Clonal Generation
1) Saturna X L.Olimpia	40	40	40	36
2) Kiebtz X Challanger	40	40	40	31
3) Alegria X Challanger	40	40	40	19
4) Tucan X Alegria	40	39	39	39
5) Fasan X Tucan	40	39	39	34
6) Pomqueen X Tucan	40	39	39	19
7) Atlantic  X R. Russet	40	40	40	38
8) Gala X Challanger	40	40	40	19
9) Saturna X Alegria	40	40	40	33
10) Tucan X Challanger	40	39	39	30

Table 1. Correlation coefficients between BPS values and evaluated plant traits

Seedling Generation BPSHw BPSTbr PH 0,6624** 0,1934 ST 0,573** 0,4567** LW 0,0806 0,0989 LH 0,6957** 0,5512** TS 0,2407** -0,0443 TED 0,178* 0,2689** TSS -0,1517 -0,0275 TSC 0,0707 0,0725 TNT 0,292** 0,6541** TWT 0,6855** 0,7061** BPSTbr 0,4809 First Clonal Generation BPSHw BPSTbr PH 0,79** 0,3278** ST 0,752** 0,3492** LW 0,0317 0,0711 LH 0,2099* 0,1468 TS 0,073 0,2194* TED 0,0416 0,1407 SS 0,1253 0,0104 SC 0,1352 0,0682 TNT 0,4308** 0,3969** TWT 0,6146** 0,7621** BPSTbr 0,5015**                    Seedlin      Clonal BPSHw BPSTbr BPSHw 0,1793** 0,2356** BPSTbr 0,1951** 0,1371* **p>0,01,; p>*0,05 PH = Plant Height , TED= Tuber Eyes Depth, ST = Stem Thickness , TSS = Tuber Skin Smoothness, LW = Leaf Width                      TSC = Tuber Skin Color, LH = Leaf height, TNT = Total Number of Tubers, TS = Tuber shape, TWT=  Total Weight of Tubers, BPSHw = Breeder Preference Score  for  Haulms, BPSTbr = Breeder Preference Score  for Tubers Key results ØThe stem diameter, leaf length, tuber eye depth, number of tubers per plant and tuber weight per plant were significantly correlated with both BPSHw and BPSTbr in seedling generation . ØIn seedling generation, the correlation between BPSHw and BPSTbr were also significant.  ØIn the first clonal generation, plant height, stem diameter, number of tubers per plant and tuber weight per plant  were found as significant. ØThe skin color can be used as a selection criteria starting from the seedling generation, while using tuber shape or eye depth as a selection criteria in seedling generation is not reliable for the subsequent generations.