scholarly journals Metering Nonuniform Vegetable Seed

1998 ◽  
Vol 8 (1) ◽  
pp. 69-71 ◽  
Author(s):  
Richard L. Parish ◽  
Regina P. Bracy

Selecting the proper seeder setup to meter a given seed lot effectively can be very difficult for a vegetable grower, especially if the seed lot is not graded for size uniformity. A belt-type seeder should effectively singulate the seeds if the seeds are spherical and uniform because the holes are specifically sized. Seeds that are not graded for size uniformity may not be singulated effectively by a belt-type seeder. A vacuum-type seeder should uniformly meter a wider range of seed sizes better than a belt-type seeder since the holes in the seed plate must only be smaller than the smallest seeds in the lot. Seed lots (graded and ungraded) of two turnip (Brassica rapa L. rapifera group) cultivars were metered with a belt seeder using belts with holes 6/64 inch (2.4 mm) or 7/64 inch (2.8 mm) in diameter or with a vacuum seeder. Neither the belt nor vacuum seeder satisfactorily singulated any of the seed lots. With the larger (7/64 inch) belt holes, there were excessive incidences of multiple seeds per drop. With the smaller (6/64 inch) belt holes, multiple drops and missed seed were excessive. The vacuum seeder also resulted in excessive misses and multiples.

HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 598c-598
Author(s):  
Richard L. Parish ◽  
Regina P. Bracy

Selecting the proper seeder setup to effectively meter a given seed lot can be very difficult for a vegetable grower, especially if the seed lot is not graded for size uniformity. A belt-type seeder should be able to effectively singulate the seeds if the seeds are spherical and uniform because the holes are specifically sized. Seeds that are not graded for size uniformity may not be singulated effectively by a belt-type seeder. A vacuum-type seeder should be able to uniformly meter a wider range of seed sizes better than a belt-type seeder since the holes in the seed plate must only be smaller than the smallest seeds in the lot. Seed lots (graded and ungraded) of two cultivars of turnip (Brassica rape L. Rapifera group) were metered with a belt seeder using belts with holes 6/64 inch (2.4 mm) or 7/64 inch (2.8 mm) in diameter or with a vacuum seeder. Neither the belt nor vacuum seeder resulted in satisfactory singulation with any of the seed lots. With the larger [7/64 inch (2.8 mm)] belt holes, there were excessive incidences of multiple seeds per drop. With the smaller [6/64 inch (2.4 mm)] belt holes, multiple drops and missed seed were both excessive. The vacuum seeder also resulted in excessive misses and multiples.


Genetika ◽  
2020 ◽  
Vol 52 (1) ◽  
pp. 215-228
Author(s):  
Bahram Dehdar ◽  
Saleh Amiri ◽  
Bahman Panahi ◽  
Reza Mohammadi

In potatoes (Solanum tuberosum L. 2n=4x=48) both the general combining ability (GCA) effects of parents and specific combining ability (SCA) of crosses are important in conditioning traits of economic importance. The objective of this study was to determine the combining abilities for tuber yield and its components on seven high-yielding commercial cultivars of potato and advanced potato clones. Significant differences were found between the parents in the all of traits that are associated with high genetic diversity between parents. GCA for tuber form, length of stolon and number of tuber per plant were high and for stem height, tuber skin appearance and eye dept were low. Heritability estimated from 49 percent in the number of stem to 84 percent in tuber skin appearance. Both heritability and genetic advance as percent of mean estimates were high for tuber yield, tuber form, length of stolon, tuber size, and number of tuber per plant and tuber size uniformity. AS10, AS12, AS14 and UT43 clones was best general combiner for the tuber yield, tuber size uniformity, eye depth, tuber dry matter and length of stolon. The SCA effects were the highest in the cross Savalan?UT43, Luca?AS20, Stbr2?Savalan and Picasso?HS in the traits were considered. Savalan and UT43 parents used in the crosses also have high GCA in studied traits. Finally results showed that Savalan, UT43, AS10, AS12 and AS14 in the studied traits was the high GCA and better than other parents.


2020 ◽  
Vol 10 (2) ◽  
pp. 79
Author(s):  
Kezia Sisilia Sagay ◽  
Parluhutan Siahaan ◽  
Susan Mambu

ABSTRAKSawi hijau (Brassica rapa L. var. Tosakan ) adalah salah satu komoditi sayuran yang sudah banyak dibudidayakan. Kebutuhan masyarakat terhadap sawi hijau semakin meningkat sehingga dari permintaan konsumen sawi hijau layak dikembangkan. Faktor penting dalam budidaya tanaman yang menunjang keberhasilan produksi sawi hijau yaitu pemupukan. Penelitian ini bertujuan untuk menguji respon pertumbuhan tanaman sawi hijau (Brassica rapa L. var. Tosakan ) akibat pemberian PGPR (Plant Growth-romoting Rhizobacteria) yang dikombinasikan dengan pupuk kompos maupun NPK. Penelitian ini terdiri atas lima perlakuan yang diulangi sebanyak lima kali: P0 (tanah kebun sebagai kontrol), P1 (tanah kebun ditambah pemberian PGPR), P2 (tanah kebun, kompos ditambah pemberian PGPR), P3 (tanah kebun ditambah pupuk NPK dengan pemberian PGPR), P4 (tanah kebun ditambah NPK). Hasil penelitian menunjukan bahwa PGPR dapat meningkatkan pertumbuhan sawi hijau yang lebih baik dibandingkan dengan kontrol. Kombinasi PGPR yang memberikan hasil terbaik adalah perlakuan  PGPR yang dikombinasikan dengan pupuk NPK.Kata kunci: Sawi hijau; PGPR; Pupuk kompos; Pupuk NPK. ABSTRACTGreen mustard (Brassica rapa L. var. Tosakan) is a vegetable commodity that has been widely cultivated. Community needs for green mustard are increasing, so that the demand for green mustard consumers is worth developed. An important factor in crop cultivation that supports the success of mustard greens production is fertilization. Study aims to examine the growth response of green mustard plants (Brassica rapa L. var. Tosakan) due to the administration of PGPR (Plant Growth-romoting Rhizobacteria) combined with compost or NPK fertilizer. This study consisted of five treatments that were repeated five times: P0 (farmland as a control), P1 (garden land plus PGPR application), P2 (garden land, compost plus PGPR application), P3 (garden land plus NPK fertilizer with granting PGPR), P4 (garden land plus NPK). The results of the study showed that PGPR could generally increase the growth of green mustard better than controls. The combination of PGPR that provided the best results was the PGPR and NPK fertilizer combination.Keywords: Green mustard, PGPR, Compost fertilizer, NPK fertilizer.


1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.


Author(s):  
J. Frank ◽  
P.-Y. Sizaret ◽  
A. Verschoor ◽  
J. Lamy

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.


Author(s):  
A. V. Crewe

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.


Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.


Author(s):  
P.R. Swann ◽  
A.E. Lloyd

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.


Author(s):  
K.C. Newton

Thermal effects in lens regulator systems have become a major problem with the extension of electron microscope resolution capabilities below 5 Angstrom units. Larger columns with immersion lenses and increased accelerating potentials have made solutions more difficult by increasing the power being handled. Environmental control, component choice, and wiring design provide answers, however. Figure 1 indicates with broken lines where thermal problems develop in regulator systemsExtensive environmental control is required in the sampling and reference networks. In each case, stability better than I ppm/min. is required. Components with thermal coefficients satisfactory for these applications without environmental control are either not available or priced prohibitively.


Author(s):  
D. Cherns

The use of high resolution electron microscopy (HREM) to determine the atomic structure of grain boundaries and interfaces is a topic of great current interest. Grain boundary structure has been considered for many years as central to an understanding of the mechanical and transport properties of materials. Some more recent attention has focussed on the atomic structures of metalsemiconductor interfaces which are believed to control electrical properties of contacts. The atomic structures of interfaces in semiconductor or metal multilayers is an area of growing interest for understanding the unusual electrical or mechanical properties which these new materials possess. However, although the point-to-point resolutions of currently available HREMs, ∼2-3Å, appear sufficient to solve many of these problems, few atomic models of grain boundaries and interfaces have been derived. Moreover, with a new generation of 300-400kV instruments promising resolutions in the 1.6-2.0 Å range, and resolutions better than 1.5Å expected from specialist instruments, it is an appropriate time to consider the usefulness of HREM for interface studies.


Sign in / Sign up

Export Citation Format

Share Document