Improving apple rootstock tolerant to Iron chlorosis.

Iron chlorosise is very prevalent in arid and semi arid regions especially in sandy soils. The apple tree is sensitive to chlorosise arising from calcareous soils, this project was performed to approach to apple rootstocks tolerance to chlorosise in Karaj from 2005-2007. The required seeds were collected native apple germplasem from different region of country. The chlorophyll content was measured in 23044 intact leaves of 1130 apple sapling in sharp growing period by CCM-200 Chlorophyll Content Meter. The results of this research indicated that the maximum average of Chlorophyll Content is 90,45 in genotype Morabaei No.٥٩and least average was 12,79 in genotype Abbasi No. 186. The 287 genotypes with average Chlorophyll Content over 40 were selected and planted in field with 5٪additive calcareous at end of March 2005.The results indicated that the correlation between chlorophyll a and b was 0,854 in 242 genotype. The Corolation between total chlorophyll with chlorophyll in 663 nm and 645 nm was 0,934 and 0,983 respectively. The corolation between amount accruing from CCM-200 with total chlorophyll and 645 nm, 663 nm were 0,408, 0,383, and 0,403 respectively. For investigating rooting potential of selected genotypes, hard wood cuttings were taken all at January and February 2007. The cuttings treated with IBA hormone and planted in completely randomized design. The cutting of 65 genotypes had potential of root producing. All of Genotypes were divided in 7 clusters for rooting capacity. Some genotypes Such as No. 31 and 30 with 55٪rooting were settled in first group and genotypes No. 7, 9, 28 and 201 in second group. The commercial vegetative rootstocks of B9, M9 and M26 could not produce root. Other 255 genotypes did not produce roots. All of Genotypes were divided in 9 clusters from rooting and callus producing point of view. 122 genotypes produced root and callus. The genotype No.1 was settled in first group with 77٪percent callus producing. The commercial vegetative rootstocks of B9, M9 and M26 were settled in 7 clusters with 11٪of callus producing. The seedlings of Morabaei had not any rooting and callus producing.