Respon of seven sweetpotato clones on three levels of field capacity on Entisol soil Kawi

English. Sweet potato grown on upland soils occasionally undergoes drought stress that its growth and productivity are hampered significantly. A reduction in growth and production are obviously discerned on less tolerant varieties to drought condition. A study was undertaken under green house condition at RILET-Malang from June to October 1999, and aimed at examining the response of sweet potato clones on the water availabilities. Treatments were arranged in Split Plot design and replicated 4 times. The water availabilities (A = 35 percent water content of field capacity, B = 45 percent water content of field capacity, C = 55 percent water content of field capacity) and sweet potato clones (1 = MIS104-1, 2 = MIS110-1, 3 = MIS146-1, 4 = MLG12569-4, 5 = Genjah Sawo, 6 = Cangkuang, 7 = IR Melati Merah) were as main plot and sub-plot, respectively. The study revealed that water availability and sweet potato clones affected the wilting of vines, the length of the vines at 45 and 75 days after planting (dap), the contents of chlorophyll-a and b, the number of stomata, the number and weight of tubers, and vine dry weight. The longest plant was attained at 55 percent water content of field capacity, while the shortest one was observed at 35 percent water content of field capacity. Clones MIS110-1 and Cangkuang showed longer plant than MIS104-1, MLG12569-4 and IR Melati Merah. Four clones contained higher chlorophyll-a at 35 percent, one clone at 45 percent, and 2 clones at 55 percent water content of field capacity. The highest number of stomata at 45 dap, was observed at 35 percent water capacity on MIS104-1. The weight of the vine increased with increasing water availabilities, and MIS104-1 depicted the highest. On the basis of the tubers weight, MLG12569-4, MIS104-1 and Genjah Sawo revealed index of tolerance higher than the rest of the clones tested. Such clones, showing relatively high index of tolerance, could be grown on upland-dry soils

Indonesian. Ubijalar yang ditanam di lahan tegal sering mengalami kekeringan sehingga pertumbuhan dan produktivitasnya menurun secara nyata. Hal ini mungkin disebabkan oleh kerentanan varietas ubijalar yang ditanam terhadap kurangnya air tersedia di dalam tanah. Penelitian dilakukan untuk mengetahui tanggapan beberapa klon ubijalar terhadap tingkat ketersedian air tanah yang dilaksanakan di rumah kaca Balitkabi-Malang pada bulan Juni-Oktober 1999. Rancangan yang digunakan adalah Petak Terbagi dengan empat ulangan. Sebagai petak utama adalah taraf pemberian air dan anak petak adalah tujuh klon ubijalar. Perlakuan pemberian air terdiri atas tiga taraf yaitu A = kadar air tanah 35 persen KL (kapasitas lapang), B = kadar air tanah 45 persen KL, dan C = kadar air tanah 55 persen KL. Parameter yang diamati adalah kesegaran tajuk berlaku nilai 1 s/d 5, panjang sulur pada umur 45 dan 75 hari setelah tanam (HST), jumlah stomata, kadar klorofil-a, bobot basah/kering tajuk, jumlah dan berat umbi saat panen dan indeks toleransi. Hasil penelitian menunjukkan bahwa tingkat pemberian air dan klon berpengaruh terhadap kelayuan tajuk, panjang sulur pada umur 45 dan 75 HST, kadar khlorofil-a dan khlorofil-b, jumlah stomata, jumlah dan berat umbi/tanaman, serta bobot tajuk. Rataan sulur terpanjang dicapai pada 55 persen KL dan terpendek pada 35 persen KL. Klon MIS110-1 dan Cangkuang memiliki sulur lebih panjang daripada klon MIS104-1, MLG12569-4 dan IR Melati Merah. Empat klon memiliki kadar khlorofil-a tinggi pada 35 persen KL, 1 klon pada 45 persen KL, dan 2 klon pada 55 persen KL. Rataan jumlah stomata tertinggi pada umur 45 HST dan 35 persen KL dimiliki oleh MIS104-1. Rataan bobot tajuk meningkat secara nyata dengan meningkatnya pemberian air dan tertinggi dicapai oleh MIS110-1 atas dasar hasil umbi per tanaman MLG12569-4, MIS104-1 dan Genjah Sawo menunjukkan nilai indeks toleransi relatif lebih tinggi daripada klon lainnya. Klon-klon yang memiliki fenotipe demikian dapat dikembangkan di daerah kering