Microsatellites...
Microsatellites are the simple sequence repeats which are highly polymorphic in nature as it is based on hyper variable repeat region in the genome. Therefore, SSR becomes the marker of choice for constructing linkage map. The other markers can also be used for such purposes.
Our objectives...
- Developing a suitable mapping population.
- Parental survey for the polymorphism across the parents and F1.
- Surveying the segregating population with the selected markers.
- Estimating the linkage between the markers and construction of linkage map.
Linkage Mapping
Elite cultivars Maharaji and Red Delicious were used as parents for creating the mapping population, as these have a number of contrasting attributes ranging from planta type to fruit traits. Controlled crossing was successfully carried out in 2011 and again in 2012 (as a back-up resource) to generate pseudo-test cross sib families (also reciprocal) using ‘Plus’ trees at two locations in Kashmir. We have now established a large number of hybrid seedlings from the crossing work. Our preliminary analysis of these seedlings reveal them to be true segregating hybrids and thus suitable for mapping/linkage analysis.
Details of apple mapping population seedlings (2011 Cross) available in the Botanical Garden
Cross | No. of seeds sown | No. of seeds germinated | No. of seedlings presently growing |
---|---|---|---|
Delicious (F) X Maharaji (M)-Srinagar | 320 | 235 | 204 |
Delicious (F) X Maharaji (M)-Shopian | 197 | 159 | 129 |
Delicious (M) X Maharaji (F) | 285 | 168 | 140 |
Total | 802 | 562 | 473 |
Details of crossing experiment (2012 Cross) in apple (Backup mapping population)
Cross | No. of crosses | No. of hybrid fruits produced | No. of hybrid seeds harvested | No. of seeds sown | No. of seeds germinated |
---|---|---|---|---|---|
Delicious (F) X Maharaji (M) | 810 | 92 | 405 | 200 | 160 |
Delicious (M) X Maharaji (F) | 1240 | 250 | 1370 | 400 | 290 |
Total | 2050 | 342 | 1775 | 600 | 450 |