Intensification of Cotton-Wheat System to Cotton-Potato-Wheat System Through Inclusion of Potato in Northwestern Plains

A field experiment was conducted at Project Directorate for Farming Systems Research Modipuram, Meerut during 2005–07 for the evaluation of cotton, potato and wheat genotypes in system mode for intensification and profitability of cotton-wheat system. Highest seed-cotton yield was recorded in LHH 144 (2.5 t ha⁻¹) followed by Ankur 2534 (2.4 t ha⁻¹), while lowest was in CNH 36 (2.0 t ha⁻¹). Seed-cotton yield was highly correlated with biomass (r=0.884), boll numbers harvested (r=0.785) and boll weight (r=0.888) as observed in LHH 144, Ankur 2534 and Ankur 651. Photosynthesis (Pn, µmole m⁻² s⁻¹) and photosynthetic water use efficiency (PWUE, mmole CO₂ mole⁻¹ H₂O) was higher in cotton hybrids (26–28 and 2.7–3.1, respectively) than varieties (24–25 and 2.5–2.6, respectively). Among potato genotypes, Kufri Pukhraj had significantly higher tuber yield and tuber numbers (22.5 t ha⁻¹ and 366 x 1000 ha⁻¹, respectively) than Kufri Surya (17.3 t ha⁻¹ and 287 x 1000 ha⁻¹, respectively). Tuber dry matter content, on the other hand, was invariably higher in Kufri Surya (20.2%) than Kufri Pukhraj (17.7%). This was due to higher rate of Pn in Kufri Surya (20.0) at all the dates of plantings than Kufri Pukhraj (17.8). Late sowing of wheat by 30 and 45 days after harvest of potato significantly reduced yield (7–22%) as compared to normal sown wheat (5.3 t ha⁻¹). This was largely due to reduction in biomass (11–18%), LAI (4–18%) and shoot length (3–16%). The reduction in yield was more in PBW 343 (22%) than PBW 373 (7–16%). Among different cotton-potato based systems, WEY and net returns (NR) were significantly higher with Ankur 2534 (19.03 t ha⁻¹ and 101.7 x 1000 Rs ha⁻¹, respectively) and Ankur 651 (18.94 t ha⁻¹ and 101.0 x 1000 Rs ha⁻¹, respectively) cotton hybrids. Similarly in potato, higher WEY and NR were observed with Kufri Pukhraj (19.63 t ha⁻¹, and 108.1 x 1000 Rs ha⁻¹, respectively) than Kufri Surya (17.31 t ha⁻¹, and 85.9 x 1000 Rs ha⁻¹, respectively). The results indicate that early maturing cotton genotypes (Ankur 651, Ankur 2534 and LHH 144) and potato genotypes (Kufri Pukhraj and Kufri Surya) could provide opportunities for further intensification and enhancing net returns of cotton-wheat system by inclusion of potato in northwestern plains in system mode.