POTENSI HASIL GALUR-GALUR F1 MANDUL JANTAN KAPAS PADA PERSILANGAN ALAMI

ABSTRAK<br />Produksi benih varietas kapas hibrida dapat ditempuh dengan dua<br />cara, yaitu dengan persilangan manual dan dengan memanfaatkan galur<br />mandul jantan (male-sterile line). Memproduksi benih kapas secara<br />persilangan manual memerlukan tenaga dan biaya yang tinggi, dan biaya<br />tersebut dapat dikurangi dengan menggunakan galur male steril. Penelitian<br />dilaksanakan di Kebun Percobaan Balai Penelitian Tanaman Tembakau<br />dan Serat, di Karangploso, Malang, Jawa Timur, dari bulan April sampai<br />Oktober 2007. Tujuan penelitian ini adalah untuk mengetahui potensi hasil<br />galur-galur mandul jantan kapas untuk memproduksi benih hibrida. Tiga<br />aksesi kapas yaitu KI 487, KI 489, dan KI 494 yang memiliki persentase<br />tanaman mandul jantan masing-masing 60,8%, 57,5%, dan 65% telah<br />digunakan sebagai donor sifat mandul jantan dan telah dilakukan introgresi<br />sifat mandul jantan dari ketiga aksesi tersebut ke varietas komersial<br />Kanesia 7, Kanesia 8, dan Kanesia 9 melalui persilangan pada tahun 2006<br />dan diperoleh 9 set kombinasi persilangan. Pada tahun 2007, evaluasi<br />potensi galur dilakukan terhadap 8 galur F1 mandul jantan, 3 tetua jantan<br />yaitu varietas Kanesia 7, Kanesia 8, dan Kanesia 9, serta satu varietas baru<br />yaitu Kanesia 12 sebagai pembanding yang disusun dalam rancangan acak<br />kelompok yang diulang 3 kali. Plot percobaan berukuran 3 x 10 m 2<br />dengan jarak tanam 100 cm x 25 cm; satu tanaman per lubang. Dosis<br />pupuk yang digunakan adalah 100 kg urea + 100kg ZA + 100kg SP 36 +<br />100kg KCL per ha. Tidak dilakukan pengendalian hama dengan<br />insektisida kimia selama penelitian. Pengamatan yang dilakukan adalah<br />kemandulan benangsari secara visual dan mikroskopis, jumlah buah per<br />tanaman, bobot buah, dan hasil kapas berbiji. Hasil penelitian<br />menunjukkan bahwa pengamatan secara visual dan mikroskopis terhadap<br />struktur bunga menunjukkan bahwa semua individu tanaman dari 8 galur<br />F1 yang diuji adalah mandul jantan. Jumlah buah galur mandul jantan 7 –<br />96% lebih banyak tetapi ukuran buahnya lebih kecil dibandingkan dengan<br />Kanesia. Galur-galur mandul jantan KI 494 x Kanesia 7 dan KI 494 x<br />Kanesia 8 memberikan hasil kapas berbiji paling tinggi masing-masing<br />2.609kg dan 2.153kg per hektar dibandingkan dengan galur-galur lain,<br />atau sebesar 94 % dan 95% dibandingkan dengan Kanesia 7 dan Kanesia<br />8. Persilangan alami galur-galur tersebut bervariasi sebesar 51 – 95%.<br />Kata kunci : Kapas, Gossypium hirsutum. L., mandul jantan, benih hibrida<br />ABSTRACT<br />Cotton yield potential of F1 male sterile lines under<br />natural crossing<br />Cotton hybrid seed production can be done by manual crossing and<br />by using male steril line methods. The manual crossing technique is<br />however labor dan cost intensive, and the cost can only be reduced by<br />using male sterile lines. The experiment was conducted in Karangploso<br />Experimental Station of Indonesian Tobacco and Fiber Crops Research<br />Institute (IToFCRI), Malang, East Java, from April to Oktober 2007<br />aiming to evaluate the yield potential of cotton male sterile lines. Three<br />cotton accessions e.i KI 487, KI 489, and KI 494 which have male sterility<br />percentage of 60.8%, 57.5%, and 65%, respectively, were used as donor<br />for male sterility and were then introgressed to three commercial cotton<br />variety, Kanesia 7, Kanesia 8, and Kanesia 9 through manual crossing, and<br />that resulted in nine sets of crossing combinations. In 2007, yield potential<br />were studied including 8 F1 male sterile lines, 3 male parent lines (Kanesia<br />7, Kanesia 8, and Kanesia 9), and one new cotton variety, Kanesia 12, as<br />control in a randomized block design with 3 replications. Plot size was 3 x<br />10 m 2 with 100 cm x 25 cm plant spacing; one plant per hill. Fertilizer<br />dosage was 100kg urea + 100kg ZA + 100kg SP 36 + 100kg KCl per ha.<br />Chemical insecticide was not used for insect protection during the<br />research. Parameters observed were plants male sterility, number of bolls<br />per plant, boll weight, and seed cotton yield. The experimental result<br />showed that both visual and microscopic observation of male sterility on<br />individual plants confirmed that the eight F1 lines tested were male sterile.<br />Number of bolls per plant of male sterile lines were 7 – 96% higher than<br />that of Kanesia’s, but boll size was smaller. Lines KI 494 x Kanesia 7 and<br />KI 494 x Kanesia 8 produced highest cotton seed yield of 2609 kg and<br />2153 kg per hectar, respectively, which were 94% and 95% of that of their<br />male parents, Kanesia 7 and Kanesia 8, respectively. Natural crossing of<br />those lines varied around 51 – 95%.<br />Key words : Cotton, Gossypium hirsutum. L., male sterile, hybrid seed

Interspecific grafting to solve the rootstock shortage in vegetative propagation of Lai-durian (Durio zibethinus x kutejensis) originated from East Kalimantan

Lai-durian (Durio zibethinus x kutejensis) is a durio species derived from a natural crossing between Durio zibethinus (Durian, local name) and Durio kutejensis (Lai, local name) showing high performance of fruit quality and economic value such as golden yellow aril color, sweet and odourless taste, soft and dry texture, long shelf life (7-10 days), high edible portion, and relatively high fruit weight and yield per plant per year. The vegetative propagation of Lai-durian especially using shoot or bud grafting is facing a problem due to the low rootstock availability since Lai-durian seeds show a high percentage of abnormal/undeveloped seeds. This research was performed to evaluate the compatibility and growth performance of the interspecific grafting of two different grafting types, chip budding and cleft grafting using three different rootstock sources, D. zibethinus, D. kutejensis, and D. zibethinus x kutejensis. Three superior national varieties of Lai-durian, i.e., Lai Kayan, Lai Mandong, and Holai Sentawar were used in this research as scion sources. The total number of 180 grafting occasions of chip budding and cleft grafting was conducted using 4–5 months-old seedling plants with 50-60 cm height as rootstocks. The survival rate of the successful grafting and several growth parameters, i.e., plant height, shoot and rootstock diameter, leaf number, and branch number increment were evaluated for two months. The interspecific grafting of Lai-durian on three different rootstock seedlings derived from D. zibethinus, D. kutejensis, and D..zibethinus x kutejensis was compatible and showed a successful graft union using chip budding (94%) or cleft grafting (60%). The use of D. zibethinus and D. kutejensis as rootstocks could replace those of D. zibethinus x kutejensis since there were no significant differences in the grafting compatibility and growth among the three varieties of rootstocks.

The elephant in the room: How a technology’s name affects its interpretation

In this work, using experiments, we investigate the role of the name of a technology on the informed evaluation of that technology. We argue that a name can influence interpretations by activating cognitive structures. Using genomics-accelerated breeding as a case, we show that the name ‘genomics’ makes people evaluate related information as similar to genetic modification. Replacing the name ‘genomics’ with ‘natural crossing’ causes evaluations similar to those for traditional breeding. The results show that a name can have a strong influence on public attitudes, and we call for more consideration in choosing a name for a technology.

Suitability of Hybrid Acacia Wood for Manufacturing Plywood and Particleboard

Hybrid acacia, produced from natural crossing between two introduced timber species Acacia mangium and A. auriculiformies has been studied for assessing the suitability of plywood and particleboard manufacture. It was found that 1.5 mm thick smooth and figured veneer can be made and dried easily. Three-ply plywood were made using veneer of this species bonded with liquid urea formaldehyde glue of 50% solid content extended with wheat flower and catalyzed (ammonium chloride) with 2% hardener under the specific pressures, viz., 1.05, 1.40 and 1.76 N/mm2 in three replications at 6 minute press time and 120°C press temperature. Dry and wet shear test were conducted on the sample and their shear load at failure per unit area and percentage of wood failure were determined. 1.76 N/mm2 pressure for the manufacture of ply wood is found to be the best. The particleboard was tested for determining the strength and dimensional stability. The bending strength passed the standard specification, tensile strength was found to be low as per Indian standard. DOI: http://dx.doi.org/10.3329/jbas.v36i2.12960 Journal of Bangladesh Academy of Sciences, Vol. 36, No. 2, 171-176, 2012

Resistance to Septoria lycopersici in Solanum (section Lycopersicon) species and in progenies of S. lycopersicum × S. peruvianum

Septoria leaf spot (Septoria lycopersici) is one of the major fungal diseases of tomatoes (Solanum lycopersicum) in tropical and subtropical regions with humid climates and/or in areas cultivated under sprinkler irrigation systems. Sources of resistance have been found in accessions of Solanum (section Lycopersicon) species. However, many of the described sources are not effective under Brazilian conditions. The objective of this work was to evaluate wild and cultivated Solanum (section Lycopersicon) germplasm to S. lycopersici isolates. A collection of 124 accessions was initially evaluated under greenhouse conditions. Ten accessions were highly resistance (HR), whereas 33 were classified as having a resistant (R) response to S. lycopersici isolates. Field evaluation was also conducted with a sub-set of accessions identified as either HR or R in the greenhouse experiment. This field evaluation confirmed greenhouse tests and indicated the presence of some potential sources of rate-reducing resistance. One highly resistant and eight resistant S. habrochaites accessions were identified as being resistant under both conditions, confirming that this wild species is one of the most promising sources of resistance to S. lycopersici. Five new sources with high levels of resistance were found in S. peruvianum accessions (PI-306811, CNPH-1036, LA-1910, LA-1984 and LA-2744). One accession derived from an interspecific cross between S. lycopersicum and S. peruvianum was also found to be highly resistant and might be useful to introgress resistance factors from this wild species into cultivated tomato germplasm. However, additional breeding efforts will be necessary to introgress into the cultivated tomato the resistance factors identified in other S. peruvianum accessions due to the presence of natural crossing barriers between the two species.

Natural crossing and isolation distance between cotton genotypes in turkey

The purposes of this study were to determine the percentage of out-crossing, isolation distance and pollinator insect species for cotton (Gossypium hirsutum L.) seed production in the Aydin region in Turkey. The glandless and red-leaf traits in G. hirsutum were used as genetic markers. Two experiments were conducted over two years that monitored out-crossing in adjacent rows and adjacent plants and established that the percentage of out-crossing varied. The percentage of out-crossing varied between 0% and 13.3% depending on the genetic marker. In the experiment to determine isolation distance, natural crossing percentage was not observed in 2002, while this percentage was 0.8% in the first rows in 2003. In this study, cotton fields were also visited once a week during flowering periods for seven weeks in order to determine the numbers of pollinator insect species, where the only detected species was the honey bee. The numbers of pollinator insects were 2.14% (2002) and 1.30% (2003) for adjacent rows; 1.71% (2002) and 2.00% (2003) for adjacent plants in glandless parcels. It is recommended that the isolation distance between genotypes should be approximately 1 m.

Crossing rate and distance in upland rice

Rice (Oryza sativa L.) is an autogamous species that shows natural crossing rates of up to 3%, where the variations are influenced by genotypes and environments. The present work aimed to evaluate the rates and distances of natural crossing between the upland rice cultivars Guarani and IAC 201. The study was done in the counties of Carpina and Recife, in the State of Pernambuco during the agricultural years of 2001 and 2002, respectively. The Guarani cultivar presents leaf pilosity conditioned by the dominant alleles HLHL and this character was used as a morphologic tracer. On the other hand, the IAC 201 cultivar does not show pilosity because it carries the recessive alleles (hlhl). The experiments were composed of four blocks, constituting of ten circunscribed rows of the cultivar under study, spaced 50 cm between themselves, and in the center of each block the Guarani cultivar was planted. The natural crossing rate and distance were evaluated in the plants resulting from the seeds of the IAC 201 cultivar from natural crossing, expressing pilosity in the leaves. After the evaluation of the plants arising from the first two rows of the experiment carried out in Carpina and the first three rows of the experiment done in Recife, it was concluded that in the first row (0.5 m) there were plants resulting from natural crossing. At this distance, the average crossing rate in Carpina was 0.30% while that in Recife was 0.35%.