Plant height heterosis is quantitatively associated with expression levels of plastid ribosomal proteins

The use of hybrids is widespread in agriculture, yet the molecular basis for hybrid vigor (heterosis) remains obscure. To identify molecular components that may contribute to trait heterosis, we analyzed paired proteomic and transcriptomic data from seedling leaf and mature leaf blade tissues of maize hybrids and their inbred parents. Nuclear- and plastid-encoded subunits of complexes required for protein synthesis in the chloroplast and for the light reactions of photosynthesis were expressed above midparent and high-parent levels, respectively. Consistent with previous reports in Arabidopsis, ethylene biosynthetic enzymes were expressed below midparent levels in the hybrids, suggesting a conserved mechanism for heterosis between monocots and dicots. The ethylene biosynthesis mutant, acs2/acs6, largely phenocopied the hybrid proteome, indicating that a reduction in ethylene biosynthesis may mediate the differences between inbreds and their hybrids. To rank the relevance of expression differences to trait heterosis, we compared seedling leaf protein levels to the adult plant height of 15 hybrids. Hybrid/midparent expression ratios were most positively correlated with hybrid/midparent plant height ratios for the chloroplast ribosomal proteins. Our results show that increased expression of chloroplast ribosomal proteins in hybrid seedling leaves is mediated by reduced expression of ethylene biosynthetic enzymes and that the degree of their overexpression in seedlings can quantitatively predict adult trait heterosis.

Micropropagation in vitro of essential oil rose hybrids obtained in embryoculture

The aim of the work was to study the features of clonal micropropagation of essential oil rose interspecific hybrids obtained in embryo culture in vitro. Analysis of 12 crossing combinations demonstrated that the frequency of hybrid seedling formation in the embryo culture varied from 0 to 71.4%. For clonal micropropagation obtained in vitro seedlings were divided into stem segments with a node and cultivated on MS culture medium supplemented with 0.5 mg/l BAP and 0.1 mg/l GA3. During the multiplication of 13 hybrids (R. alba × R. damascena cv. ‘Kazanlykskaya’) in 2-6 subcultures, high variability of the multiplication index (1.8-18.5 depending on the genotype and passage) was revealed. This parameter was maximum in the 3-4th subcultures. The best ability to micropropagation showed hybrid No. 37-14. Microshoots were rooted in vitro on ½ MS medium, containing for different hybrids 0.5 or 1.0 mg/l NAA; frequency – up to 80.5-100.0%. However, in No. 37-2, 37-19 and 37-31 on four tested media, the number of shoots with roots was only 0-35.4%.

Gibberellins and Heterosis in Crops and Trees: An Integrative Review and Preliminary Study with Brassica

Heterosis, or hybrid vigor, has contributed substantially to genetic improvements in crops and trees and its physiological basis involves multiple processes. Four associations with the phytohormone gibberellin (GA) indicate its involvement in the regulation of heterosis for shoot growth in maize, sorghum, wheat, rice, tomato and poplar. (1) Inbreds somewhat resemble GA-deficient dwarfs and are often highly responsive to exogenous GA3. (2) Levels of endogenous GAs, including the bioeffector GA1, its precursors GA19 and GA20, and/or its metabolite GA8, are higher in some fast-growing hybrids than parental genotypes. (3) Oxidative metabolism of applied [3H]GAs is more rapid in vigorous hybrids than inbreds, and (4) heterotic hybrids have displayed increased expression of GA biosynthetic genes including GA 20-oxidase and GA 3-oxidase. We further investigated Brassica rapa, an oilseed rape, by comparing two inbreds (AO533 and AO539) and their F1 hybrid. Seedling emergence was faster in the hybrid and potence ratios indicated dominance for increased leaf number, area and mass, and stem mass. Overdominance (heterosis) was displayed for root mass, leading to slight heterosis for total plant mass. Stem contents of GA19,20,1 were similar across the Brassica genotypes and increased prior to bolting; elongation was correlated with endogenous GA but heterosis for shoot growth was modest. The collective studies support a physiological role for GAs in the regulation of heterosis for shoot growth in crops and trees, and the Brassica study encourages further investigation of heterosis for root growth.

Modeling the hybrid seedling performance of forage sorghum and silage corn under Jordan irrigation conditions

The beta casein gene (CSNS2) has 12 genetic variants divided into two groups: the first group (A1, B, and G) which differ from the second group (A2, A3 C, D, E, F, H, H2 and I) where A base replaces C base, this leads to potential liberation of a bioactive peptide, b-casomorphin, upon digestion where a histidine replaces a proline at position 67. The allele specific polymerase chain reaction (AS-PCR) was evaluated to distinguish between the beta casomorphin releasing variants (A1 and B) and the non-releasing variants. The sequence analysis was used to determine these variants and confirm it in goat, sheep and cattle. The results showed that cattle carrying allele A1 either homozygous or heterozygous more than sheep and goats. The allele frequency of A1 and A2 is 0.44, 0.56 in goats, 0.43, 0.57 in sheep and 0.54, 0.46 in cattle, respectively. The sequence results reported changing of C base to A base in goat, sheep and cattle. Therefore, this study reported that goat and sheep milk was more safe than cattle milk.

Penampilan Bibit Kelapa F1 Hasil Silangan Genjah x Dalam Mapanget S4

<p><span style="font-size: medium;">ABSTRAK </span></p><p>Tanaman kelapa yang ditanam petani umumnya tipe kelapa Dalam dengan pertambahan tinggi batang cepat. Ketersediaan tenaga pemanjat saat ini semakin sulit didapat, sehingga dibutuhkan varietas kelapa yang berbuah cepat, berbatang pendek dan pertambahan tinggi batang lambat. Varietas kelapa tersebut dapat dirakit dengan menyilangkan kelapa Genjah dengan kelapa Dalam yang pertambahan tinggi batangnya lambat. Penelitian ini bertujuan untuk mengetahui penampilan bibit dua genotipe kelapa hibrida hasil persilangan Genjah Kuning Bali (GKB), Genjah Raja (GRA) dengan Dalam Mapanget generasi selfing ke-4 (DMT-S4) serta Genjah Kuning Nias (GKN ) x Dalam Tenga (DTA) atau Khina-1 sebagai pembanding. Penelitian menggunakan Rancangan Acak Kelompok (RAK) dengan tiga perlakuan dan sembilan ulangan, masing-masing ulangan terdiri dari 12 tanaman. Perlakuan yang diuji adalah A = GKB x DMT-S4, B = GRA x DMT-S4 dan C = GKN x DTA. Hasil penelitian pertumbuhan dan perkembangan tingkat bibit dari ketiga genotipe kelapa hibrida tersebut memperlihatkan bahwa kecambah dari hibrida hasil persilangan GKB x DMT-S4 memiliki viabilitas tertinggi yang diikuti oleh hasil persilangan GKN x DTA dan GRA x DMT-S4. Kecepatan kecambah dan kecepatan pecah daun bibit ketiga hibrida tersebut tidak berbeda nyata. Jumlah daun bibit hasil persilangan GKN x DTA lebih banyak dari hasil persilangan GKB x DMT-S4 dan GRA x DMT-S4 (umur 2 hingga 5 bulan), namun pada umur 6 bulan jumlah daun bibit hasil persilangan GKB x DMT S4 (7,75 helai) tidak berbeda nyata dengan GKN x DTA (7,97 helai). Rata-rata pertambahan daun/bulan bibit dari setiap hibrida tersebut adalah: 1,28 helai (GKB x DMT S4), 1,13 helai (GRA x DMT S4) dan 1,21 helai (GKN x DTA). Berdasarkan penelitian ini diketahui bahwa bibit hasil persilangan GKB x DMT S4 dan GRA x DMT S4 lebih pendek dengan lingkar batang lebih kecil dibanding GKN x DTA. Bibit kelapa hibrida hasil persilangan GKB x DMT S4 dan GKN x DMT S4 memberikan harapan dapat diperoleh varietas kelapa yang cepat berbuah, berbatang pendek dan batang lambat menjadi tinggi.</p><p>Kata kunci: Kelapa hibrida, bibit, pendek, cepat berbuah.</p><p> </p><p><strong><span style="font-size: medium;"><span style="color: black; line-height: 115%; letter-spacing: -0.35pt; font-family: 'Arial Bold'; font-size: 14pt; mso-bidi-font-family: 'Arial Bold'; mso-font-width: 96%; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: IN; mso-fareast-language: IN; mso-bidi-language: AR-SA; mso-fareast-theme-font: minor-fareast;">Coconut Hybrid Performance of Dwarf x Mapanget Fourth Selfing Generation</span></span></strong></p><p><span style="font-size: medium;">ABSTRACT </span></p><p>Coconut palm planted by farmers is generally Tall type coconut which grows fast. Availability of climbers is limited, therefore, coconut varieties that are early mature, short and slowly growing trunk are needed. The coconut varieties can be assembled by crossing Dwarf coconut palm with Tall coconut palm which slowly growing trunk. This research aims to know the appearance of hybrid coconut seedlings from crosses of two superior varieties Dwarf coconut Bali Yellow Dwarf (BYD), Raja Dwarf (RBD) with Mapanget Tall Fourth Selfing Generation (MTT S4) and Nias Yellow Dwarf (NYD) x Tenga Tall (TAT) or Khina-1 as a comparison. This experimental was arranged in Randomized Block Design (RBD) with three treatments and nine replications, each replication was consisted of 12 palms. The treatment is A = BYD x MTT-S4, B = RBD x MTT-S4 dan C = NYD x TAT. Results showed that hybrid from BYD x MTT S4 has the highest viability followed by NYD x TAT and RBD x MTT S4. Germination rate and leaf splitting time of three hybrid were not significantly different. More over leaves number of NYD x TAT is more than that of BYD x MTT S4 and RBD x MTT S4 (ages 2 to 5 months), but at the age of 6 months, leaves number of BYD x MTT S4 (7.75) was not significantly different from NYD x TAT (7.97). While the average leaves increase per month of each hybrid are: 1.28 (BYD x MTT S4), 1.13 (RBD x MTT S4) and 1.21 (NYD x TAT). The result of this study showed that coconut hybrid from BYD x MTT S4 and RBD x MTT S4 are shorter than NYD x TAT. Hybrid lines of BYD x MTT S4 and RBD x MTT S4 have a smaller girth of seedling than coconut hybrid of NYD x TAT. Coconut hybrid lines of BYD x MTT S4 and RBD x MTT S4 are promising in producing coconut varieties that early mature, short and slowly growing trunk.</p><p>Keywords: Coconut hybrid, seedling, dwarf, early mature.</p>

Genetic Parameters of Interspecific Hybrids of Eucalyptus grandis and E. urophylla Seedlings and Cuttings

The current E. grandis × E. urophylla hybrid breeding strategy of South Africa’s Forestry Industry is to maintain large breeding populations of both parental species in which parents are selected based on their general combining ability (GCA) estimates or predicted individual tree breeding values and are used for interspecific hybrid crosses. The hybrid material is first screened in seedling progeny trials after which superior individuals are selected and tested as clones. Although this strategy has delivered superior clones for commercial production in South Africa, it is a time consuming strategy to follow and more cost effective strategies are being investigated. In order to review the current hybrid breeding strategy, information on the genetic control of the traits of interest is needed for E. grandis × E. urophylla seedling and clonal populations. The main objectives of this study were therefore to firstly estimate genetic parameters for E. grandis × E. urophylla hybrid seedling and clonal populations; secondly to investigate the correlation between E. grandis and E. urophylla parental (GCA) or individual breeding values and their general hybridising ability (GHA); and lastly to determine the correlation between E. grandis × E. urophylla hybrid seedling ortets and their ramets. Results of our study indicated that non-additive genetic variation explained the majority of the total genetic variation in E. grandis × E. urophylla seedling and clonal populations. Due to the pre-eminence of non-additive variance, the pure-hybrid correlations were weak, especially for clonal populations. It would therefore seem that GCA or predicted individual breeding values are not good predictors of GHA for growth performance in the observed populations. Our study also indicated a weak coefficient of correlation between the growth performance of seedling ortets and their ramets. These results suggest that: firstly a hybrid breeding strategy to capture non-additive genetic variation should be adopted; and secondly that the first phase of screening E. grandis × E. urophylla hybrid material as seedlings should be revisited.