Trench layering technologies for rapid multiplication of Elite Apple Germplasm (Malus domestica) in Kabale, Western Uganda.

Abstract

Apples greatly contribute to farmers’ livelihoods in tropical highlands. However, there has been limited access to quality planting materials associated with poor rooting of apple rootstocks. To improve rooting ability, this experiment was setup at Bugongi Research Station Orchard to examine the effects of TsaOm (Top forest soil +Sand+ Organic matter) and TsdOm (Top forest soil + Saw dust +Organic matter) substrate mixtures and IBA concentrations [0 (control), 4000 ppm and 8000 ppm] on the rooting success and survivability of M106, M109, MM793 and Bitten felder Apple rootstocks. A completely randomized design with three replicates in factorial arrangement was used. The rooting percentage increased markedly to 76.02% in bitten felder and up to100% in M106. The highest (37.39±0.12) and lowest (13.04±0.3) rooting percentages were obtained in M109 and MM793 respectively with TsdOm. While TsaOm and TsdOm resulted in higher rooting percentages in MM793, it was the reverse in bitten felder. The application of TsdOm on M106 and M109 resulted in significant increases in root numbers and a reduction in the survivability of M106. The survivability of M109, MM793 and Bitten felder layers increased significantly in TsaOm and TsdOm mixtures, but the highest survival rate (45.1± 0.2) was obtained in M109 under TsaOm mixture. With IBA concentrations, 8000 ppm gave the highest (41.22 ± 0.11%) in M109 as and the lowest rooting percentage (8.4 ± 0.0%) in M106 respectively. IBA concentrations had significant effect on root lengths with the longest (9.9 ± 2.2 cm) recorded in M106 after treatment with 4000 ppm. The lowest root length was obtained in MM793 after treatment with 8000 ppm. A significantly difference in survival rates was exhibited by the interaction of apple rootstocks and IBA concentrations. These results indicate that trench layering technologies that incorporate appropriate organic substrate mixtures (TsaOm and TsdOm) and IBA at 4000 ppm are suitable for rapid multiplication of apple rootstocks which could increase farmer’s access to quality germplasm.