## 4 Discussion
The smallest GS of turnip landrace was reported in our study is from Qinghai province from altitudinal environment above 3600 m. Thus, we showed that turnip landraces adapted in the QTP are morphologically and genetically different compared to the landraces adapted in the Himalaya and the Hengduanshan region which we hypothesize due to the adaptation in the extreme climate [29]. This might be due to the fact that ultraviolet spectrum of the QTP is much stronger compared to the Himalayas and Hengduanshan resulting in a significant decrease in GS [39]. Then, we interrogated the question whether morphological and genomic plasticity of turnip landraces across the roof of the world is interlinked. To confirm our speculation, we did correlation analyses between GS and morphological traits. Investigation revealed GS variation was neither associated with morphological traits (LL, ABM, TD, and UGB) nor with reproductive traits (SS and SW). Three separate groups (cluster I to III) were observed in PCA, landraces were intermixed from one cluster to another. For instance, some landraces from the Himalaya environment (cluster II) got mixed with turnip landraces from the Hengduanshan (cluster I:KTRG-B-77, KTRG-84, KTRG-86, and KTRG-B-85) and QTP (cluster III: KTRG-B-81) (Figure 6). Some differences in landrace usage were also observed among the landraces from the south Asian agroclimates. For instance, the least number of vectors were pointing towards landraces from the extreme climate of Tibet (KTRG-B-03, KTRG-B-05, and KTRG-B-49) and Uttarakhand (KTRG-B-81) demonstrating their least usage. On the other hand, landraces from Tibet (KTRG-B-57), Sichuan (KTRG-B-19), Hengduanshan (KTRG-B-33, KTRG-B-37, KTRG-B-54, KTRG-B-55, KTRG-B-61, and KTRG-B-65), and Paro (KTRG-B-77, KTRG-B-84, KTRG-B-85, and KTRG-B-86) received higher landrace usage as demonstrated by PCA. This skewed distribution of landrace usage happened due to the fact that China enjoys a monopoly in turnip production and most of the Brassicamembers are under strong selection pressure for breeding. Moreover, the nonsignificant correlation of GS with morphological parameters and environmental factors (apart from latitude and altitude) might happen on account of adaptation to farmer's selection [40]. It might be due to lack of undertaking of phylogenetic correction in our correlation analyses, which would have better resolving power for predicting selection pressure on intraspecific scale. The variability in oil and protein content in the seed reserve may encounter for this kind of nonsignificant correlation which was not tested in our investigation. It is envisaged that plant growth form, GS, precipitation, and temperature are factors controlling SW [12]. GS increase causes gradual increase in cell size of seed parts (seed coat, embryo, and endosperm) resulting in increased mass of the seed [12]. Although GS is correlated with several phenotypes in plants [12], GS and SS/SW correlation in turnip was not significant in our investigation. Similar observations were also reported by other scholars too in wild and cultivated plant materials [5; 8; 13]. Literature supports this result as it is not imperative that GS variation should always be accompanied by changes in phenotype [41]. The results presented here support the generalization made by [PERSON] et al. [12] that the maximum SW for any given GS may be controlled by other factors. Since SS/SW was not also influenced by the precipitation and temperature, we may conclude that plant growth form (annual vs. biennial, generation time, and growth habit) may be the factor controlling the SS/SW in different regions. Among the morphological features investigated, UGB was strongly affected by environmental variation but not SS/SW. The environment (latitude, altitude, temperature, and drought) seems to play a pivotal role in shaping GS by imposing selection pressure on physiology and life history traits that are correlated with GS [42].