Forty-five superior genotypes (or “pipeline clones”) of Para rubber tree (Hevea brasiliensis) were screened for their adaptability to sub-optimal environments of India viz. Agartala (Tripura State) and Dapchari (Maharashtra State), which experience cold and drought stresses, respectively. The clones were evaluated for their growth and yield in clonal nurseries at the above two sites along with a comparative trial in a traditional environment (Chethackal, Kerala). Of the two sub-optimal environments, clones displayed better growth and yield at Agartala suggesting better adaptability of these clones to cold stress. Analysis of genetic parameters also supported this trend. The pipeline and control clones showed the lowest girth and yield in Dapchari environment which is prone to severe drought conditions. However, the clones had better girth and yield in Agartala, which is affected by cold stress, than in the conditions of Chethackal. For girth and yield, the broad-sense heritability estimated at the clonal level was lower in Dapchari than in the other two environments. Under cold-prone environment, five clones P 102 (35.8 cm), P 107 (35.6 cm), P 021 (34.7 cm), P 101 (32.1 cm) and P 059 (31.5 cm) achieved better or similar girth when compared to control clones, RRII 429 (33.9 cm), RRII 430 (32.8 cm) and abiotic stress-tolerant clone RRIM 600 (31.7 cm). Under drought stress environment, two clones P 102 (25.4 cm) and P 026 (21.8 cm) gave better girth than drought-tolerant clone RRII 208 (20.6 cm). Under traditional environment at Chethackal, control clone PB 260 (28.6 cm) along with RRII 414 (27.5 cm) achieved better girth. In terms of yield, P 107 (124.8 g/t/10t) gave maximum yield in the cold environment. In the same environment, P 057 (113.2 g/t/10t) gave a yield comparable with that of high-yielding control clone RRII 430 (114.5 g/t/10t). In the drought-prone region, control clone RRII 430 (57.1 g/t/10t) gave maximum yield. Three clones P 026 (52 g/t/10t), P 061 (47.6 g/t/10t) and P 015 (44.3 g/t/10t) also gave better yield as compared to control clone RRIM 600 (42.7 g/t/10t). Two clones P 027 (43.0 g/t/10t) and P 060 (42.7 g/t/10t) gave a yield which was comparable with RRIM 600 (42.7 g/t/10t). Eleven clones gave better yield than the region-specific control clone RRII 208 (38.2 g/t/10t). Under traditional environment, the control clone RRII 430 (130.8 g/t/10t) gave highest yield. Among clones, P 074 (112.1 g/t/10t) gave high yield as compared to control clone RRII 414 (111.9 g/t/10t). Two clones P 044 (106.0 g/t/10t) and P 026 (102.5 g/t/10t) gave better yield than control clone PB 260 (99.5 g/t/10t). Three clones P 015 (99.5 g/t/10t), P 110 (99.0 g/t/10t) and P 078 (98.4 g/t/10t) gave good yield comparable with control clone PB 260. Eleven clones gave better yield performance than control RRII 105 (66.6 g/t/10t). Twelve clones with superior growth and yield were identified as candidate clones for cold-prone environment. Similarly, twelve clones were identified as candidate clones for drought-prone environment. Eleven clones were identified as potential candidate clones for the traditional environment. Based on overall performance in terms of growth and yield under drought and cold environments, four clones P 020, P 026, P 102 and P 107 and the hybrid control clone RRII 430 were identified as having potential to evolve into climate-resilient clones. Two clones P 020 and P 026 along with the control clone RRII 430 appeared to possess multifarious adaptability for traditional as well as sub-optimal environments.

巴西橡胶树 ( Hevea brasiliensis ) 的45 个优良基因型（或“管道克隆”）) 筛选了它们对印度次优环境的适应性，即。Agartala（特里普拉邦）和 Dapchari（马哈拉施特拉邦）分别经历寒冷和干旱胁迫。在上述两个地点的克隆苗圃中评估了克隆的生长和产量，并在传统环境（喀拉拉邦 Chethackal）中进行了比较试验。在两个次优环境中，克隆在 Agartala 显示出更好的生长和产量，表明这些克隆对冷胁迫的适应性更好。对遗传参数的分析也支持了这一趋势。管道和对照克隆在容易发生严重干旱条件的 Dapchari 环境中显示出最低的周长和产量。然而，在受冷胁迫影响的 Agartala 中，克隆的周长和产量比在 Chethackal 条件下更好。对于周长和产量，Dapchari 在克隆水平上估计的广义遗传力低于其他两种环境。在寒冷环境下，与 P 102 (35.8 cm)、P 107 (35.6 cm)、P 021 (34.7 cm)、P 101 (32.1 cm) 和 P 059 (31.5 cm) 相比，五个无性系获得了更好或相似的周长对照克隆、RRII 429 (33.9 cm)、RRII 430 (32.8 cm) 和非生物胁迫耐受克隆 RRIM 600 (31.7 cm)。在干旱胁迫环境下，两个无性系 P 102 (25.4 cm) 和 P 026 (21.8 cm) 的周长优于耐旱无性系 RRII 208 (20.6 cm)。在 Chethackal 的传统环境下，对照克隆 PB 260 (28.6 cm) 和 RRII 414 (27.5 cm) 获得了更好的围度。就产量而言，P 107 (124.8 g/t/10t) 在寒冷环境中的产量最高。在相同环境下，P 057 (113. 2 g/t/10t) 的产量与高产对照克隆 RRII 430 (114.5 g/t/10t) 相当。在干旱易发地区，对照克隆 RRII 430 (57.1 g/t/10t) 产量最高。与对照克隆 RRIM 600 (42.7 g/t) 相比，三个克隆 P 026 (52 g/t/10t)、P 061 (47.6 g/t/10t) 和 P 015 (44.3 g/t/10t) 也提供了更好的产量/10 吨）。两个克隆 P 027 (43.0 g/t/10t) 和 P 060 (42.7 g/t/10t) 的产量与 RRIM 600 (42.7 g/t/10t) 相当。11 个克隆的产量高于区域特异性对照克隆 RRII 208 (38.2 g/t/10t)。在传统环境下，对照克隆RRII 430（130.8 g/t/10t）的产量最高。在克隆中，与对照克隆 RRII 414 (111.9 g/t/10t) 相比，P 074 (112.1 g/t/10t) 产量高。两个克隆 P 044 (106.0 g/t/10t) 和 P 026 (102. 5 g/t/10t) 的产率高于对照克隆 PB 260 (99.5 g/t/10t)。三个克隆 P 015 (99.5 g/t/10t)、P 110 (99.0 g/t/10t) 和 P 078 (98.4 g/t/10t) 的产量与对照克隆 PB 260 相当。十一个克隆提供了更好的产量性能比对照 RRII 105 (66.6 g/t/10t)。12 个具有优异生长和产量的克隆被确定为易冷环境的候选克隆。类似地，12 个克隆被确定为干旱易发环境的候选克隆。11 个克隆被确定为传统环境的潜在候选克隆。根据干旱和寒冷环境下生长和产量方面的整体表现，四个无性系 P 020、P 026、P 102 和 P 107 以及杂交对照无性系 RRII 430 被确定为具有进化成气候适应性无性系的潜力。