truit seed slralifiefl in iiulividual pots with metal labels ready to be buried 

 in t3ie soil over winter for planting the next spring. 



Breeding Tetraploid Apples 



III the spring of 1950, Dr. L. F. Hough, New Jersey Agricultural Experi- 

 ment Station, furnished seeds of Kimball 4n Mcintosh x Wrixparent. The 

 latter was the only other tetraploid apple readily available for pollen for 

 crossing with the Kimball 4n Mcintosh at Littleton, Massachusetts, in 1949. 

 Wrixparent is a large green apple. A progeny of 75 seedlings of this cross 

 i? being grown at Durham, New Hampshire, and some should fruit in one 

 or two more years. Their value may be mostly for use in further breeding 

 work to produce good triploid varieties. 



Breeding for Resistance to Apple Scab 



In 1955. the New Hampshire Station entered actively a cooperative pro- 

 ject with three other states — New Jersey, Indiana, and Illinois — to breed 

 scab-resistant apples. For several years previous to 1955, trees at Durham, 

 New Hampshire, were used for parents in making of crosses with those 

 apple varieties or species showing a high degree of resistance to apple scab. 

 The seeds were sent to Indiana and Illinois where the seedlings were started, 

 tested for susceptibility to scab in the greenhouse, and then the resistant 

 ones grown to fruiting in the open field. Not until 1955 were the first seed- 

 lings that had been screened for resistance to scab planted at Durham. More 

 were planted in 1956 and 1957 and a total of 620 are now growing in the 

 field. While the parentage of the several progenies varies and is not listed 

 here in full, many of the crosses have Mcintosh as one parent. Since New 

 Hampshire excels in growing the Mcintosh variety, it was considered proper 

 to grow progenies of the scab-resistant apples involving Mcintosh in their 

 ancestry to fruiting in this state. Although no fungicide was applied to the 

 seedlings in 1955 and 1956, the leaves of all seedlings showed freedom from 

 apple scab. Powdery mildew has. however, become serious in these scab 

 resistant progenies, so much so that it has been necessary to apply a sulphur 

 dust to the foliage of the trees to prevent loss of leaves and a dieback of the 

 twigs. Mildew restricted seriously the growth of some of the seedlings in 1956. 



